LIBRARY 

OF    THE 

UNIVERSITY  OF  CALIFORNIA. 
Class 


QUANTITATIVE 

METALLURGICAL 

ANALYSIS 


QUANTITATIVE   METAL- 
LURGICAL   ANALYSI S 


SELECTED  METHODS  FOR 
CHEMICAL  ANALYSIS  OF  ORES, 
SLAGS,  COAL,  PIG  IRON  AND  STEEL 


Arranged  by 

CHARLES  FREDERICK  SIDENER,  B.  S. 

\( 

Assistant  Professor  of  Chemistry,  University  of  Minnesota 


The  H.  W.  WILSON  COMPANY 

MINNEAPOLIS 

1904 


BOOKS  OF  REFERENCE. 

C.  R.  Fresenius — Quantitative  Analysis. 
F.    Cairns — Quantitative  Analysis. 
H.    Furman — A  Manual  of  Practical  Assaying. 
A.   A.    Blair — The  Chemical  Analysis  of  Iron. 
N.  W.   Lord — Notes  on   Metallurgical   Analysis. 
M.  Troilius — Notes  on  the  Chemistry  of  Iron. 
J.    O.   Arnold — Steel  Works  Analysis. 
F.    C.    Phillips,   Ed.— Methods  of  Iron  Analysis   in   the 
Laboratories  about  Pittsburg,  Pa. 


VOLUMETRIC  IODIDE  METHOD  FOR  THE  DETERMIN- 
ATION OF  COPPER  IN  COPPER  ORES. 

MODIFIED  BY  A.  H.  Low. 

The  method  depends  upon  the  following  reaction: 

2Cu(C2H302)2+4KI  =  Cu2I2+4KC2H302+I2. 
Cuprous  iodide  precipitates  and  a  proportionate  amount  of  iodine 
is  set  free,  which  may  be  determined  by  titration  with  sodium  thio- 
sulphate.    The  reaction  is :  2Na2S2O3  +  2l=2NaI+Na2S4O6. 

The  standard  solution  required  is  that  of  sodium  thiosulphate 
which  may  be  prepared  by  dissolving  19.59  grams  of  the  pure 
salt  in  a  liter  of  water,  and  standardizing  as  follows : 

Weigh  out  into  two  flasks  of  200-300  c.c.  capacity  two  por- 
tions of  copper  foil  of  about  0.2  gram  each.  Dissolve  by  warming 
with  5  c.c.  of  dilute  nitric  acid  (sp.  gr.  1.2).  Boil  for  a  few 
moments  to  partially  expel  the  red  fumes  and  then  add  5  c.c.  of 
strong  bromine  water  and  boil  until  the  bromine  is  thoroughly 
expelled.  The  bromine  is  to  insure  the  complete  destruction 
or  removal  of  the  red  fumes.  Remove  from  the  heat  and  treat 
the  solution  by  one  of  the  following  methods  to  change  the  cop- 
per into  the  form  of  copper  acetate,  (a)  Add  a  slight  excess  of 
ammonia  water  and  boil  until  the  excess  of  ammonia  is 
expelled,  as  shown  by  a  change  of  color  of  the  liquid  and  a 
partial  precipitation  of  the  copper  as  hydroxide  or  oxide  Now 
add  strong  acetic  acid  in  slight  excess,  perhaps  3  or  4  c.c.  of  the 
80  per  cent  acid  in  all,  and  boil  again  for  a  moment  if  necessary 
to  redissolve  the  copper,  (b)  Add  20  c.c.  of  a  cold  saturated 


144194 


2  METALLURGICAL  ANALYSIS 

solution  of  zinc  acetate  and  heat  the  solution  to  boiling, 
(c)  Add  sodium  carbonate  till  a  permanent  precipitate  occurs 
and  then  acetic  acid  until  the  precipitate  dissolves,  and  heat 
the  solution  to  boiling.  Free  mineral  acids  decompose  the  iodide 
of  potatssium,  therefore  no  free  acid  stronger  than  acetic  should  be 
present.  The  condition  is  attained  by  any  one  of  the  above  meth- 
ods. Cool  the  solution  to  the  ordinary  temperature,  and  dilute 
with  water  to  about  50  c.c.  Add  3  grams  of  potassium  iodide 
and  shake  gently  until  the  salt  dissolves.  Titrate  the  solution  im- 
mediately with  the  thiosulphate  until  the  brown  color  is  nearly 
destroyed.  Add  I  or  2  c.c.  of  starch  solution,  and  continue 
the  titration  until  the  blue  color  disappears.  Calculate  the  strength 
of  the  thioslilphate  solution  in  terms  of  copper. 

Process — Treat  one  gram  of  the  pulverized  ore  in  a  covered 
casserole,  under  a  hood,  with  7  c.c.  of  concentrated  nitric  acid 
and  gently  heat  for  a  few  moments ;  add  five  c.c.  of  concentrated 
hydrochloric  acid  and  again  heat  for  a  short  time.  Then  add 
five  c.c.  of  concentrated  sulphuric  acid  and  evaporate  until  dense 
fumes  of  sulphuric  anhydride  are  evolved.  Cool ;  add  50  c.c.  of 
water  and  heat  until  the  sulphates  of  copper,  iron,  etc.,  have  dis- 
solved. Filter  into  a  small  beaker,  wash  with  a  little  hot  water 
and  endeavor  to  keep  the  volume  of  the  filtrate  down  to  about 
50  or  60  c.c. 

Place  in  the  beaker  two  pieces  of  aluminium  about  il/2  inches 
square,  1//16  inch  thick,  with  the  four  corners  bent  for  i/£  inch  al- 
ternately up  and  down  at  right  angles.  Add  five  c.c.  of  concen- 
trated sulphuric  acid,  cover  the  beaker  and  heat  to  boiling.  Boil 
for  eight  or  ten  minutes.  Unless  the  bulk  of  the  solution  is  ex- 
cessive, this  will  generally  be  sufficient  to  precipitate  all  of  the  cop- 
per. Transfer  the  solution  to  a  flask  of  200  to  300  c.c.  capacity, 
rinsing  in  with  hot  water,  as  much  of  the  copper  as  possible.  Al- 
low the  copper  in  the  flask  to  settle  and  decant  the  liquid  through 
a  filter,  wash  the  copper  two  or  three  times,  retaining  it  as  com- 
pletely as  possible  in  the  flask.  Pour  upon  the  aluminium  in  the 
beaker  five  c.c.  of  dilute  nitric  acid  (sp.  gr.  1.2)  warm  gently  until 
the  copper  is  dissolved.  Then  pour  the  solution  through  the  filter, 
receiving  the  filtrate  in  the  flask  containing  the  main  portion  of 
the  coppei.  At  this  stage  do  not  wash  either  the  aluminium  or 


METALLURGICAL  ANALYSIS  3 

the  filter,  but  simply  remove  the  flask  and  set  the  beaker  in  its 
place. 

Heat  the  contents  of  the  flask  to  dissolve  the  copper;  add  5  c.c. 
•of  strong  bromine  water  and  boil  for  a  moment  to  oxidize  any 
arsenic  present  to  arsenic  acid.  Remove  the  flask  from  the  lamp 
and  again  place  it  under  the  funnel.  Now  wash  the  beaker,  alu- 
minium and  filter  with  as  little  hot  water  as  possible.  Boil  to  re- 
move the  excess  of  bromine  but  avoid  boiling  to  such  a  small  bulk 
as  to  cause  decomposition  of  bromides,  etc. 

Change  the  copper  into  the  form  of  copper  acetate,  add  about 
3  grams  of  potassium  iodide  and  titrate  with  the  thiosulphate 
precisely  as  described  above  in  the  standardization  of  the  thio- 
sulphate. 


References  on  sampling  ores  : 

Win.   Glenn,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  XX,  page  155. 
Rattle  and  Nye,  Jour.  An.  &  App.  Chem.,  Vol.  V,  page  299. 
N.   W.    Lord,  Notes  on  Metallurgical  Analysis. 
A.  A.  Blair,  The  Chemical  Analysis  of  Iron. 


^References  on  copper  : 

H.  Furman,  A  Manual  of  Practical  Assaying. 

A.  H.  Low,  Jour.  Am.  Chem.  8oc.,  Vol.  XVIII,  page  458. 

A.    H.    Low,  Jour.  Am.   Chem.  Soc.,  Vol.  XXIV,  page  1082. 


VOLUMETRIC  DETERMINATION  OF  COPPER  BY 
POTASSIUM  CYANIDE  SOLUTION. 

The  method  depends  upon  the  fact  that  the  addition  of  potas- 
•sium  cyanide  to  an  ammoniacal  copper  solution  affords  a  colorless 
solution.     The  reaction  is  : 
2Cu  ( NH3 )  4  ( N03 )  ,H2CH-8KCN= 

^[Cu0(CN)0fK4+NH4CNO-fNH4CN+6NH3+4KNO3. 

The  standard  solution  required  is  potassium  cyanide,  which 
may  be  prepared  as  follows :  Dissolve  30  grams  of  potassium  cyan- 
ide in  a  half  liter  of  water  and  thoroughly  mix.  To  standardize, 
weigh  out  into  two  flasks,  of  200  to  300  c.c.  capacity,  two  portions 
of  pure  copper  foil  of  about  0.3  gram  each.  Dissolve  these  in 


4  METALLURGICAL  ANALYSIS 

5  c.c.  of  concentrated  nitric  acid;   boil  off  the  red  fumes,  dilute 
slightly,  add  10  c.c.  of  ammonium  hydroxide    (sp.  gr.  .9),  cool,, 
dilute  with  water  to  about  100  c.c.  and  titrate  with  the  potassium- 
cyanide  solution  until  within  a  few  cubic  centimeters  of  the  end, 
when  the  bulk  of  the  solution  should  be  noted  and  distilled  water 
added,  if  necessary,  so  that  the  final  bulk  will  be  about  180  c.c. 
Continue  the  titration  slowly,  the  flask  being  shaken  after  each 
addition,  until  the  blue  or  lilac  tint  can  scarcely  be  discerned  at 
the  upper  edge  of  the  liquid,  when  viewed  against  a  white  back- 
ground.    Some  chemists  titrate  to  a  faint  rose  or  pink  tint.     Cal- 
culate the  strength  of  the  cyanide  solution  in  terms  of  copper, 
casserole  with  7  c.c.  of  concentrated  nitric  acid  and  gently  heat 

Process — Treat  one  gram  of  the  pulverized  ore  in  a  covered 
for  a  few  moments ;  add  five  c.c.  of  concentrated  hydrochloric 
acid  and  again  heat  for  a  short  while.  Then  add  5  c.c.  of  con- 
centrated sulphuric  acid  and  evaporate  under  a  hood  until  dense 
fumes  of  sulphuric  anhydride  are  evolved.  Cool ;  add  50  c.c.  of 
water  and  heat  until  the  sulphates  of  copper,  iron  and  so  forth 
have  dissolved  Transfer  the  contents  of  the  casserole  ta 
a  flask  of  200  to  300  c.c.  capacity,  and  add  6  grams  of  sheet  zinc, 
and  allow  to  stand  until  the  copper  is  completely  precipitated.  If 
the  action  is  too  slow  the  flask  may  be  gently  heated.  Next  add 
50  c.c.  of  water  and  20  c.c.  of  concentrated  sulphuric  acid  to  rap- 
idly dissolve  the  excess  of  zinc.  When  the  solution  of  the  zinc 
is  complete  dilute  with  water  up  to  the  neck  of  the  flask ;  allow  to 
settle,  and  decant  the  clear  supernatant  liquid;  fill  up  with  water 
and  decant  twice  more.  To  the  residue  in  the  flask,  add  5  c.c.  of 
concentrated  nitric  acid,  and  boil  to  expel  red  fumes.  Dilute  with  a 
little  water,  add  10  c.c.  of  ammonium  hydrate  (sp.  gr.  .9),  cool, 
dilute  with  water  to  about  100  c.c.  and  filter  if  necessary.  Wash: 
the  residue  with  a  little  water  and  titrate  the  copper  solution  with 
a  standard  cyanide  solution.  When  near  the  end  dilute  to  180  c.c.. 
and  finish  the  titration  as  described  above. 


Reference  :     Geo.  Ellis,  Jour.  Soc.  Chem.  Industry,  Vol.  VIII,  page- 
686. 


METALLURGICAL  ANALYSIS  5 

ELECTROLYTIC  DETERMINATION  OF  COPPER  IN 
COPPER  ORES. 

Treat  one  gram  of  the  pulverized  ore  in  a  covered  casserole, 
under  a  hood,  with  7  c.c.  of  concentrated  nitric  acid  and  heat  for 
a  few  moments,  add  5  c.c.  of  concentrated  hydrochloric  acid  and 
again  heat  for  a  short  time.  Then  add  5  c.c.  of  concentrated  sul- 
phuric acid  and  evaporate  until  dense  white  fumes  of  sulphuric 
anhydride  are  evolved.  Cool,  add  50  c.c.  of  distilled  water  and 
heat  until  sulphates  of  copper,  iron,  etc.,  have  dissolved.  Filter 
into  a  weighed  platinum  dish  and  wash  the  residue  with  a  little 
hot  water.  Connect  the  dish  with  the  negative  pole  of  a  Bunsen 
battery  of  two  cells  or  its  equivalent.  The  current  used  should  be 
of  such  a  strength  that  it  will  decompose  water  at  the  rate  of  3  to  4 
c.c.  of  oxyhydrogen  gas  per  minute.  Place  in  the.  solution  a  plati- 
num plate  or  spiral,  connected  with  the  postive  pole  of  the  battery. 
The  copper  is  deposited  upon  the  dish  and  generally  requires  from 
five  to  ten  hours  for  complete  deposition.  When  the  precipitation 
of  the  copper  appears  to  be  complete,  take  about  2  or  3  c.c.  of 
the  solution  out  by  means  of  a  pipette  and  test  it  with  a  slight 
excess  of  ammonia.  If  copper  is  found,  return  the  portion  tested 
to  the  dish,  and  continue  the  electrolysis.  If  no  blue  color  is  pro- 
duced with  ammonia  the  copper  is  all  deposited.  Quickly  remove 
the  platinum  spiral  or  plate  and  empty  the  dish,  and  wash  it  two 
or  three  times  very  carefully  with  distilled  water,  and  then  two  or 
three  times  with  alcohol,  to  wash  out  all  of-  the  water.  Dry  the 
dish  and  contents  for  a  few  seconds  in  the  drying  oven  at  about 
105°  C.  Cool  in  a  desiccator  and  weigh. 

A  platinum  cone  may  be  used  for  the  negative  electrode  in- 
stead of  the  platinum  dish.  Have  the  copper  solution  in  a  beaker 
of  about  75  c.c.  capacity.  Place  in  the  solution  the  platinum  cone 
and  platinum  spiral,  connect  the  cone  with  the  negative  pole  of  the 
battery  and  the  platinum  spiral  with  the  positive  pole  and  con- 
tinue the  electrolysis  as  above. 

COLOR  METHOD  FOR  COPPER. 
This   method   is   often   used    for   the  estimation  of   copper   in 


6  METALLURGICAL  ANALYSIS 

substances  containing  less  than  2  per  cent,  of  copper,  e.g.  in  slags 
from  copper  smelting  operations,  and  in  tailings  from  concentrat- 
ing works.  The  method  consists  in  converting  the  copper  in  a  sub- 
stance to  be  tested,  into  ammonia-copper-nitrate  and  comparing 
th  blue  color  produced,  with  that  produced  by  dissolving  the  same 
amount  of  a  standard  copper  ore,  in  the  same  amount  of  acid  and 
using  the  same  amount  of  ammonia  as  is  used  in  the  sample  to 
be  tested. 

Process — Weigh  out  the  same  amount  of  sample  and  standard, 
and  treat  with  acids  as  described  in  the  cyanide  process,  and  then 
precipitate  it  with  zinc.  The  copper  is  washed  by  decantation. 
dissolved  in  about  2  c.c.  of  nitric  acid  and  an  excess  of  ammonia 
(about  4  c.c.  sp.  gr.  .9)  added.  Dilute  with  water,  and  filter  if 
necessary,  into  the  comparison  tubes. 

Reference  :     T.  Carnelly,  Chcm.  Neics,  Vol.  XXXII,  page  303. 


TECHNICAL  DETERMINATION  OF  ZINC  IN  ORES— 

POTASSIUM    FERROCYANIDE    METHOD. 

MODIFIED  BY  A.  H.  Low. 

Preparation  of  Standard  Ferrocyanide  Solution — Dissolve  22 
grams  of  potassium  ferrocyanide  crystals  in  water  and  'dilute  to 
one  liter.  Weigh  carefully  about  o.i  gram  of  pure  zinc  and  dis- 
solve in  six  c.c.  of.  strong  hydrochloric  acid,  using  a  400  c.c. 
beaker.  Then  add  about  10  grams  of  ammonium  chloride  and  200 
c.c.  of  boiling  water.  Titrate  with  the  ferrocyanide  solution.  The 
reaction  is: 

,..ZriCl2+K4FeCn0  t=  Zn2FeCn6+4KCl. 

Continue  the  titration  until  a  drop,  when  tested  on  a  porcelain 
plate  with  a  drop  of  strong  solution  of  uranium  nitrate,  shows  a 
brown  tinge.  The  reaction  is : 

K4FeCn6+2Uo2  (  No3  )  2=  (Uo2  )  2FeCn6+4KNO3. 
When    the    titration    is    about    finished,    the    reaction    is    much 
sharper  if  several  drops  are  placed  in  the  depression  of  the  plate 
and  tested  with  a  drop  of  uranium  nitrate.     As  this  is  near  the 


METALLURGICAL  ANALYSIS  7 

end  of  the  titration  the  amount  of  zinc  lost  by  it  is  insignificant. 
As  soon  as  a  brown  tinge  is  obtained,  note  the  reading  of  the 
burette  and  then  wait  a  minute  or  two  and  observe  if  one  or 
more  of  the  preceding  tests  do  not  also  develop  a  tinge.  The  end 
point  is  usually  passed  by  a  test  or  two  and  the  burette  readings 
must  be  accordingly  corrected.  A  further  correction  must  be 
made  for  the  amount  of  ferrocyanide  required  to  produce  a  tinge 
under  the  same  conditions  when  no  zinc  is  present.  This  is  only 
one  or  two  drops.  One  c.c.  of  the  standard  solution  will  equal 
about  .005  gram  of  of  zinc  or  about  one  per  cent,  when  0.5  gram 
is  taken  for  analysis. 

Assay   of  Ores 

To  0.5  gram  of  the  pulverized  ore  in  a  250  c.c.  pear-shaped 
flask,  add  about  2  grams  of  potassium  nitrate  and  5  c.c.  of  strong 
nitric  acid.  Heat  until  the  acid  is  about  half  gone  and  then  add 
10  c.c.  of  a  cold  saturated  solution  of  potassium  chlorate  in  strong 
nitric  acid  and  boil  to  complete  dryness.  Avoid  overheating  and 
baking.  It  is  usually  necessary  to  manipulate  the  flask  in  a  holder 
over  a  naked  flame  to  avoid  loss  by  bumping.  The  boiling  may 
be  conducted  rapidly,  and  toward  the  end  it  is  best  to  heat  the 
entire  flask  so  as  to  expel  every  trace  of  liquid.  The  potassium 
nitrate  serves  simply  as  a  diluent  of  the  dry  residue  and  insures 
the  completeness  of  the  subsequent  extraction  of  the  zinc.  Cool 
sufficiently  and  add  30  c.c.  of  a  prepared  ammoniacal  solution  and 
heat  to  boiling.  This  solution  is  made  by  dissolving  200  grams  of 
ammonium  chloride  in  a  mixture  of  500  c.c.  of  strong  ammonia 
water  arid  350  c.c.  of  water. 

Boil  the  contents  of  the  flask  gently  for  about  two  minutes 
and  then  filter  through  a  9  c.m.  filter  and  wash  with  a  hot  solution 
of  ammonium  chloride  containing  about  100  grams  of  the  salt 
and  50  c.c.  of  strong  ammonia  water  to  the  liter.  Collect  the  fil- 
trate in  a  400  c.c.  beaker.  Place  a  bit  of  litmus  paper  in  the  fil- 
trate (not  necessary  if  .much  copper  is  present)  and  neutralize 
carefully  with  hydrochloric  acid,  finally  adding  6  c.c.  of  the  strong 
acid  in  excess.  Dilute  to  about  150  c.c.  and  add  50  c.c.  of  a  cold 
saturated  solution  of  hydrogen  sulphide.  Heat  nearly  to  boiling 
and  titrate  with  standard  potassium  ferrocyanide  solution.  Make 
corrections  of  burette  readings  as  in  standardization. 

Notes. — If    the    ore    contains    considerable    arsenic    give    it    a 


8  METALLURGICAL  ANALYSTS 

preliminary  treatment  as  follows : — To  0.5  gram  of  ore  in  the  flask 
add  10  c.  c.  of  strong  hydrochloric  acid  and  one  c.  c.  of  bromine. 
Warm  gently  for  several  minutes  to  decompose  the  ore  without 
loss  of  bromine,  and  then  boil  rapidly  to  complete  dryness.  The 
arsenic  will  then  be  sufficiently  expelled.  Now  add  the  potassium 
nitrate'  and  nitric  acid  and  proceed  as  above.  If  the  ore  contains 
much  copper  and  cadmium  it  may  be  necessary  to  pass  a  cur- 
rent of  hydrogen  sulphide  gas  into  the  hot  solution  to  precipitate 
them  instead  of  using  the  water  solution  of  the  hydrogen  sul- 
phide. If  the  precipitate  is  very  large  it  had  better  be  filtered 
off  and  the  filtrate  titrated  as  usual. 

Ores  containing  copper  but  no  cadmium  the  copper  can  be 
best  precipitated  with  test  lead  without  the  use  of  hydrogen  sul- 
phide as  follows :  After  neutralizing  the  ammoniacal  filtrate 
from  the  insoluble  residue  acidify  with  an  excess  of  10  c.c. 
of  concentrated  hydrochloric  acid  and  add  about  30  grams  of 
test  lead.  Heat  nearly  to  boiling  and  stir  the  lead  about  until 
the  copper  is  all  precipitated.  Now  dilute  to  200  c.c.  and  titrate 
as  described  without  removing  the  lead  and  precipitated  copper. 

References  : 

Jour.  An.  &  App.  Chem.,  Vol.  XI,  page  491. 

A.  H.  Low,  Jour.  Am.  Chem.  Soc.,  Vol.  XXII,  page  198. 


DETERMINATION  OF  LEAD  IN  LEAD  ORES. 

VOLUMETRIC     METHOD ALEXANDER'S. 

This  method  is  based  on  the  fact  that  ammonium  molybdate 
when  added  to  a  hot  solution  of  lead  acetate  will  give  a  pre- 
cipitate of  molybdate  of  lead  PbMoO4,  which  is  insoluble  in 
acetic  acid.  An  excess  of  ammonium  molybdate  will  give  a  yel- 
low color  with  a  freshly  prepared  solution  of  tannin. 

Solution  Required — A  standard  solution  of  ammonium  molyb- 
date containing  about  nine  grams  of  salt  per  liter.  If  the  solution 
is  not  clear,  add  a  few  drops  of  ammonia. 

Indicator — A  freshly  prepared  solution  of  one  part  of  tannin 
to  300  parts  of  water. 

Standardising — Weigh   out   .3   gram   of  pure   dry  sulphate  of 


METALLURGICAL  ANALYSIS  9 

lead,  dissolve  it  in  hot  ammonium  acetate,  acidify  with  acetic 
acid  and  dilute  with  water  to  250  c.c. ;  heat  to  boiling  and  run 
in  from  a  burette  the  ammonium  molybdate  solution  till  the  lead 
is  all  precipitated. as  white  PbMoO4.  This  is  ascertained  by  plac- 
ing drops  of  indicator  on  the  porcelain  plate  and  to  them  add  a 
•drop  of  the  solution  tested  after  each  addition  of  molybdate. 
When  the  end  is  reached  the  excess  of  ammonium  molybdate  gives 
a  yellow  color  with  tannin.  The  excess  necessary  to  affect  the 
indicator  (about  7  c.c.)  must  be  determined  and  subtracted 
from  the  burette  readings.  In  titrating  it  is  essential  to  stir  the 
solution  very  thoroughly,  and  when  near  the  end  to  wait  a  few 
seconds  before  trying  the  drop  test. 

ASSAY  OF   LEAD  ORE. 

Dissolve  one  gram  of  the  finely  pulverized  ore  in  15  c.c. 
of  concentrated  nitric  acid  in  a  covered  casserole  by  the  aid 
of  heat.  Partly  cool  and  add  10  c.c.  of  sulphuric  acid  of  sp. 
gr.  1.41,  and  evaporate  till  fumes  of  sulphuric  anhydride  appear. 
Allow  to  cool  and  add  100  c.  c.  of  water  and  heat  to  boiling 
for  a  few  minutes.  Allow  to  cool  and  then  decant  through  a 
small  filter,  leaving  as  much  of  the  lead  sulphate,  silica,  etc.,  as 
possible  in  the  casserole.  Wash  thoroughly  with  dilute  sul- 
phuric acid,  then  once  with  water.  Dissolve  the  lead  sulphate 
from  the  residue,  in  the  casserole,  in  a  strong  hot  solution  of 
ammonium  acetate,  slightly  acid  with  acetic  acid.  Pour  this  so- 
lution through  the  filter  into  a  clean  beaker  and  repeat -this  until 
all  the  lead  sulphate  is  dissolved,  then  wash  the  contents  of  the 
casserole  onto  the  filter  with  hot  water.  Acidify  the  filtrate  with 
acetic  acid,  dilute  to  250  c.c.  with  hot  water  and  heat  to  boiling. 
The  solution  is  now  ready  for  titration,  which  is  done  as  in 
standardizing. 

Consult :     H.  Furman,  A  Manual  of  Practical  Assaying. 

DETERMINATION  OF  ARSENIC  IN  ORES  AND 

METALLURGICAL  PRODUCTS. 
CANBY'S    MODIFICATION    OF   PEARCE'S    METHOD. 
Mix  0.5  gram  of  the  pulverized  ore  with  about  eight  times  its 


10  METALLURGICAL  ANALYSIS 

weight  of  a  mixture  of  equal  parts  of  sodium  carborate  and  po- 
tassium nitrate,  in  a  large  porcelain  crucible.  Heat  gradually  up 
to  fusion,  and  keep  so  for  five  minutes  or  more.  Cool,  treat  with 
boiling  water,  filter  off  the  insoluble  residue  and  wasfi  it  with 
hot  water.  Acidify  the  filtrate  with  dilute  nitric  acid  and  boil 
off  the  carbonic  and  nitrous  acid  gases.  Add  an  emulsion  of 
zinc  oxide  until  it  can  be  seen  in  some  excess  in  the  bottom 
of  the  beaker  after  stirring  vigorously  and  then  allowing  a  few 
moments  to  settle.  Should  an  unusually  heavy  precipitate  of 
gelatinous  silica  and  alumina  be  produced,  filter,  wash  and  add 
more  emulsion  to  the  filtrate.  Now  add  a  slight  excess  of  silver 
nitrate,  stirring  vigorously  to  precipitate  the  silver  as  silver 
arsenate,  AggAsO4.  Filter  and  wash  with  cold  water.  Now 
place  the  beaker  in  which  the  precipitation  was  made,  under  the 
funnel,  and  dissolve  off  the  precipitate  with  dilute  nitric  acid, 
and  wash  with  cold  water.  Cool  the  solution,  and  titrate  the 
silver  with  standard  solution  of  potassium  or  ammonium  sulpho- 
cyanate,  using  i  c.c.  of  a  saturated  solution  of  ferric  sulphate 
as  indicator. 

With  potassium  sulphocyanate,  the  following  are  the  reactions : 

AgNO3-fKSCN=AgSCN-hKNO3  and 
6KSCN+ Fe2  (.SO4)3=2Fe  ( SCN )  3+3K.SO4. 

Add  the  sulphocyanate  solution  from  a  burette  until  a  faint 
amber  yellow  color  can  be  seen  in  the  solution  after  vigorous 
stirring. 

PREPARATION   AND    STANDARDIZATION   OF   THE   SULPHOCYANATE 
SOLUTION. 

Dissolve  5  or  6  grams  of  the  potassium  or  ammonium  sulpho- 
cyanate in  a  liter  of  water  and  mix  thoroughly.  The  solution 
is  standardized  by  dissolving  0.3  or  0.4  gram  of  pure  silver  in 
nitric  acid,  boiling  to  expel  red  fumes,  diluting  to  about  100  c.c. 
and  titrating  with  the  sulphocyanate  solution,  using  i  c.c.  of  the 
ferric  sulphate  (or  ferric  alum)  as  indicator.  Calculate  the 
strength  of  the  solution  in  terms  of  arsenic.  ^ 

Note  Bennett's  Modification  of  the  Pearce  Method — Decom- 
pose the  ore  by  fusion,  treat  with  water  and  filter  off  the  in- 
soluble residue.  Acidify  the  filtrate  strongly  with  acetic  acid; 
cover  and  boil  rapidly  for  a  few  minutes  to  expel  carbonic  acid. 


METALLURGICAL  ANALYSIS  U 

Cool  and  add  a  few  drops  of  phenolphthalein,  then  sodium 
hydrate  to  just  alkaline  reaction,  then  one  or  two  drops  of  acetic 
acid,  which  will  discharge  the  purple  red  color  if  too  much 
hydroxide  has  not  been  used.  The  volume  of  the  solution  should 
now  be  about  100  c.c.  Add  in  slight  excess  while  violently 
agitating  with  a  stirring  rod,  a  neutral  solution  of  silver  nitrate 
and  allow  to*  settle  for  a  few  minutes.  Filter,  wash  the  precip- 
itate with  cold  water,  dissolve  it  in  dilute  nitric  acid  and  cool. 
Dilute  to  about  100  c.c.  and  titrate  the  silver  with  a  standard  sul- 
phocyanate  solution,  using  i  c.c.  of  ferric  sulphate  as  indicator. 
Calculate  percent.  As. 

References  : 

A.  H.  Low,  Chem.  New's,  Vol.  XLVIII,  page  85. 

L.  M.  McCay,  Chem.  News,  Vol.  XLVIII,  page  7. 

Canby,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  XVII,  page  77. 

R.  Pearce,   Proc.  of  the  Colo.  8ci.  Soc.,  Vol.  I. 

J.  F.  Bennett,  Jour.  Am.  Chem.  8oc.,  Vol.  XXI,  page  431. 


DETERMINATION  OF  CHROMIUM  IN  CHROME  IRON 

ORES. 

METHOD  OF  A.  G.   MCKENNA. 

Weigh  0.5  gram  of  the  finely  ground  ore  in  a  nickel  or  iron 
crucible.  Mix  with  the  ore  three  or  four  grams  of  sodium  per- 
oxide. Hold  the  crucible  over  a  Bunsen  burner  by  means  of  a 
pair  of  tongs  and  heat  until  fusion  begins.  Keep  the  mass 
in  a  liquid  condition  at  a  low  red  heat  for  about  five  minutes.  Cool, 
then  place  crucible  and  contents  in  a  number  four  beaker  and  add 
hot  water  to  cover  the  crucible.  Cover  the  beaker  with  a  glass 
cover  and  keep  warm  until  the  fusion  dissolves.  The  chromate 
passes  into  solution,  and  the  ferric  hydroxide  remains  undissolved. 
Remove  the  crucible ;  and  heat  the  solution  to  boiling  for  fifteeen 
minutes.  Allow  the  liquid  to  cool  for  a  moment,  then  acidify 
with  dilute  sulphuric  acid  adding  10  c.c.  in  excess  of  the  amount 
necessary  to  dissolve  the  ferric  hydroxide.  The  sulphuric  acid, 
converts  the  sodium  chromate  to  sodium  bichromate. 

The    reaction    is : 

2Na2CrO4+H2SO4=Na2Cr2O7+Na2SO4+H2O. 


12  METALLURGICAL  ANALYSIS 

Dilute  the  solution  with  cold  water  to  about  300  c.c.  and  add 
70  c.c.  of  ferrous  sulphate  solution  prepared  as  follows:  Dis- 
solve 25  grams  of  ferrous  sulphate  crystals  in  water  to  which  has 
been  added  10  c.c.  of  dilute  sulphuric  acid.  Dilute  the  solution 
to  500  c.c.  and  mix  thoroughly.  The  reaction  between  the  so- 
dium bichromate  solution  and  ferrous  sulphate  in  presence  of 
sulphuric  acid  is  as  follows  : 


3Fe2(S04)3+Cr2(S04)3+Na2S04+7H20. 

Now  determine  the  excess  of  ferrous  sulphate  which  has  been 
added  by  means  of  a  standard  solution  of  potassium  permanganate 
(or  potassium  bichromate). 

Determine  the  exact  strength  of  the  ferrous  sulphate  solution 
as  follows  :  Run  out  from  a  burette  into  a  beaker  about  30  c.c.  of 
the  ferrous  solution  ;  add  about  10  c.c.  of  dilute  sulphuric  acid  ; 
dilute  to  about  150  c.c.  and  run  in  the  permanganate  from  the 
other  burette  until  the  pink  color  becomes  permanent.  Calcu- 
late the  amount  of  iron  oxidized  by  the  chromium  from  the 
chrome  ore  and  then  the  weight  of  chromium  in  solution  and  the 
percentage  in  the  ore. 

References  : 

E.  H.   Saniter,  Jour.  Soc.  Chem.  Ind.,  1896,  page  155. 
Genth,   Chem.  Neios.  Vol.  VI,  page  31. 

Kennicutt  &  Patterson,  Jour.  An.  d  App.  Chem.,  Vol.  Ill,  page  132. 
J.  Massignon,  Jour.  An.  &  App.   Chem.,  Vol.  V,  page  465. 
A.  G.  MoKenna,  Proc.  Enfj.  Soc.  Western  Pa.,  1896  &  1897. 

F.  C.  Phillips,  Ed.,  Methods  of  Analysis  in  the  Laboratories  Around 
Pittsburg,  Pa. 


PARTIAL  ANALYSIS  OF  SLAG. 

Silica — Weigh  out  .5  to  I  gram  of  the  pulverized  slag  into  a 
casserole.  Decompose  with  hydrochloric  acid  and  a  little  nitric 
acid  and  evaporate  to  complete  dryness.  Heat  the  residue  for  about 
one  hour  in  a  drying  oven  at  130°  C.  to  dehydrate  the  silica.  Add 
5  c.c.  of  hydrochloric  acid,  heat,  add  water,  heat  again  and  filter, 
wash  with  hot  water,  ignite,  and  weight  SiO  . 

If  BaSO4  is  present  treat  with  hydrofluoric  acid  and  get  the 
silica  by  loss  in  weight. 

Barium — Treat  another  portion  of  from  .5  to  i  gram  with 
hydrochloric  and  a  little  sulphuric  acid.  Evaporate  to  dryness, 


METALLURGICAL  ANALYSIS  13 

heat  until  fumes  of  sulphuric  anhydride  appear.  Add  water,  and 
hydrochloric  acid,  heat,  filter,  wash  with  hot  water  ignite  and 
weigh  SiO.,+BaSO4.  Subtract  from  this  the  SiO2  as  determined 
above  to  get  BaSO4. 

Lime — Method  I — Heat  the  filtrate  from  the  silica  to  boiling, 
add  ammonia  in  slight  excess,  and  then  a  strong  solution  of  oxalic 
acid  in  excess  to  dissolve  the  iron  and  aluminum  precipitate.  Heat 
the  solution  to  boiling  to  precipitate  calcium  oxalate.  Allow  to 
stand  for  a  short  time  to  settle,  then  filter  and  wash  thoroughly 
with  hot  water.  Place  the  funnel  over  a  clean  beaker,  and  by 
means  of  a  glass  rod  make  a  hole  in  the  filter,  and  wash  the  pre- 
cipitate through  the  funnel  into  the  beaker.  Wash  the  filter  paper 
with  a  little  hot  dilute  sulphuric  acid.  If  the  sulphuric  acid  fails 
to  dissolve  the  last  traces  of  the  calcium  oxalate  a  little  hydro- 
chloric acid  may  be  used,  and  the  filter  paper  again  washed  with 
hot  water. 

The  reaction  is  CaC2O4+H2SO4=CaSO4+H2C2O4.  Dilute  the 
solution  to  about  100  c.c.  Add  about  15  c.c.  of  sulphuric  acid, 
heat  to  about  70° C.  and  titrate  the  oxalic  acid  with  standard  per- 
manganate solution.  Calculate  the  per  cent,  of  CaO. 

Note — Tartaric  acid  may  be  used  instead  of  oxalic  acid  to  dis- 
solve the  hydroxides  of  iron  and  aluminum,  and  the  calcium  then 
precipitated  with  ammonium  oxalate.  This  method  is  not  satis- 
factory d  the  slag  contains  more  than  0.5  per  cent,  of  manganese. 

Method  II — Treat  one  gram  of  the  pulverized  slag  with  water 
and  hydrochloric  acid.  Boil  gently  until  the  slag  is  decomposed. 
Dilute  the  liquid,  nearly  neutralize  the  acid  with  ammonia.  Make 
a  basic  acetate  precipitation,  filter  and  determine  the  calcium  in 
the  filtrate  as  folows :  concentrate  the  solution  and  precipitate  the 
calcium  with  ammonium  oxalate.  Determine  the  lime  volumet- 
rically  as  in  method  I. 

Note — If  much  manganese  is  present  the  calcium  oxalate 
must  be  redissolved  and  reprecipitated  before  making  the  titration. 
Or  the  manganese  may  be  precipitated  with  bromine  and  filtered 
off  before  adding  the  ammonium  oxalate. 

Magnesia — may  be  determined  in  the  filtrate  from  the  cal- 
cium oxalate  by  precipitation  with  hydrogen  sodium  phosphate 
in  presence  of  an  excess  of  ammonia. 

Iron,   Lead,  Copper,   Manganese,   Zinc  — Follow   the   methods 


14  METALLURGICAL  ANALYSIS 

described  in  the  notes  on  the  analyses  of  various  ores,  taking  sep- 
arate portions  for  each. 


ANALYSIS  OF  BLAST  FURNACE  SLAG. 

Fuse  3  grams  of  the  finely  pulverized  slag  with  15  grams  of 
anhydrous  sodium  carbonate  and  0.5  gram  of  sodium  nitrate  in  a 
platinum  crucible.  Allow  to  cool,  decompose  the  fused  mass  with 
hot  water.  Acidify  with  hydrochloric  acid  and  evaporate  to  dry- 
ness  in  a  porcelain  dish  or  casserole  and  heat  the  residue  for 
about  one  hour  at  no°-i3O°C.  to  dehydrate  the  silicic  acid. 
Moisten  the  residue  with  concentrated  hydrochloric  acid,  warm 
gently,  add  water,  heat  and  filter  into  a  quarter  liter  graduated 
flask.  Wash  the  silica  well  with,  hot  water,  ignite  and  weigh  the 
Si02. 

Dilute  the  solution  in  the  flask  to  the  containing  mark  and 
mix  thoroughly. 

Note — Some  varieties  of  slag  are  soluble  in  hydrochloric  acid 
and  therefore  do  not  require  fusion  with  sodium  carbonate  and 
sodium  nitrate,  in  which  case  treat  the  slag  with  hydrochloric 
acid  and  a  little  nitric  acid,  evaporate  to  dryness,  dehydrate  the 
silicic  acid  and  continue  as  above. 

Determination  of  the  Iron  — Take  out  50  c.c.  of  the  solution. 
Reduce  the  iron  with  stannous  chloride  and  continue  as  directed 
on  page  2.1.  Calculate  the  per  cent,  of  Fe2O3. 

Determination  of  the  Phosphorus — To  100  c.c.  of  the  solution 
add  ammonia  until  the  mass  sets  to  a  stiff  jelly,  making  sure  that 
there  is  present  an  excess  of  ammonia.  Next  add  strong  nitric 
acid  in  sufficient  amount  to  bring  the  solution  to  a  clear  amber 
color,  and  continue  as  directed  on  page  24. 

Determination  of  Alumina,  Manganese,  Lime  and  Magnesia  — 
Take  50  c.c.  of  the  solution  in  a  large  beaker,  add  sodium  car- 
bonate until  the  fluid  is  nearly  neutral  and  then  to  the  clear  red 
liquid  add  a  solution  of  about  five  grams  of  sodium  or  am- 
monium acetate,  dilute  to  about  500  c.c.  with  boiling  distilled 
water.  Heat  to  boiling  for  a  minute  or  two,  filter  while  hot  and 
wash  by  decantation  with  hot  water.  Dissolve  the  precipitate  in 


METALLURGICAL  ANALYSIS  15 

hot  dilute  hydrochloric  acid,  add  a  little  water,  heat  to  boiling,  add 
ammonia  in  slight  excess,  filter,  and  wash  with  hot  water.  Ignite 
and  weigh  Fe.(O.{,  Al  O.,  and  P  Or.  Calculate  the  per  cent,  of 
Fe  O,,  Al  O.  and  P  (X.  The  per  cent,  of  ALO0  is  determined  by 

"2       o  2      3L,  2      0  Jo 

subtracting  the  per  cent.  Fe  O0  and  P0Or  previously  determined 

J,       o  Jo 

from  the  above. 

Add  the  filtrate  and  washings  from  the  acetate  precipitation  to 
those  from  the  precipitation  by  ammonia,  evaporate  the  solution 
to  about  200  c.c.  When  cold  add  bromine  water  until  the  solution 
is  strongly  colored,  add  ammonia  in  slight  excess  and  heat  mod- 
erately for  some  time,  then  filter  off  precipitate  of  MnO  (OH)2, 
wash  with  hot  water.  Test  filtrate  with  more  bromine  and  am- 
monia, dry,  ignite  and  weigh  Mn3O4.  Calculate  the  per  cent. 
MnO.  ; 

Instead  of  igniting  the  precipitate  of  hydrated  peroxide  of 
r.ianganese  it  may  be  dissolved  in  an  excess  of  standard  ferrous 
sulphate  solution,  containing  a  little  sulphuric  acid,  and  the  ex- 
cess of  the  ferrous  salt  determined  with  a  standard  solution  of 
permanganate  or  bichromate  of  potash.  See  Ford-Williams  pro- 
cess, page  30. 

Note — The  amount  of  calcium  carried  down  with  the  man- 
ganese depends  largely  upon  the  relative  quantities  of  calcium 
and  manganese.  WThen  the  amounts  of  each  are  over  0.02  gran? 
a  double  precipitation  of  the  manganese  should  be  made. 

When  a  slag  contains  a  very  large  amount  of  manganese  inste?d 
of  precipitating  with  bromine,  add  ammonia  to  the  solution  in 
slight  excess  and  enough  ammonium  sulphide  to  precipitate  ill 
of  the  manganese,  allow  the  precipitate  to  settle.  Filter  the 
manganese  sulphide  by  decantation  and  wash  three  times  with  a 
5  per  cent,  ammonium  nitrate  solution  containing  i  or  2  c.c.  of 
ammonium  sulphide,  finally  transfer  the  precipitate  onto  the 
filter  paper,  dry,  ignite  the  filter  paper  in  a  weighed  porcelain 
crucible,  add  the  precipitate,  heat  at  first  over  a  small  flame  with 
the  crucible  cover  off,  finally  increase  the  heat  and  at  last  heat 
over  the  blast  lamp  to  constant  weight.  Weigh  Mn3O4.  Calcu- 
late per  cent.  MnO.  Instead  of  weighing  the  manganese  as 
Mn.,O4  the  sulphide  may  be  filtered  off  and  determined  as  describ- 
ed on  page  28. 

Acidify  the  filtrate,  from  the  manganese  precipitate,  with  hy- 


16  METALLURGICAL  ANALYSIS 

drochloric  acid  and  concentrate  to  about  100  c.c.,  filter  if  nec- 
essary. Add  ammonia  in  slight  excess,  then  precipitate  the  cal- 
cium with  ammonium  oxalate  as  calcium  oxalate,  CaC0O4.  Filter, 
wash,  ignite  and  weigh  CaO.  Calculate  the  per  cent,  of  CaO.  The 
precipitate  of  calcium  oxalate  may  be  dissolved  in  dilute  sulphuric 
acid  and  the  CaO  determined  volumetrically  by  means  of  a  stan- 
dard permanganate  solution.  See  page  13. 

To  the  filtrate  from  the  calcium  oxalate  add  a  volume  of  am- 
monia of  sp.  gr.  .q6,  equal  to  one-third  the  volume  of  the  solu- 
tion. Then  add  hydrogen  sodium  phosphate  drop  by  drop  while 
stirring  the  solution  with  a  glass  rod,  to  precipitate  the  magne- 
sium as  ammonium  magnesium  phosphate.  Allow  to  stand  for 
some  time,  filter,  wash  with  a  mixture  of  one  part  of  ammonia, 
sp.  gr.  .96,  and  thiee  parts  water,  dry,  ignite  and  weigh  Mg0P0O.. 
Calculate  the  per  cent,  of  MgO. 

Determination  of  the  Sulphur — To  the  remaining  50  c.c.  of  the 
original  solution  add  a  few  drops  of  hydrochloric  acid,  heat  to 
boiling  in  a  beaker  and  precipitate  the  sulphur  with  barium  chlo- 
ride as  barium  sulphate,  BaSO4.  Calculate  the  per  cent,  of 
sulphur. 

The  above  applies  to  the  analysis  of  open  hearth  slags, 
refinery  slags,  tap  cinder,  mill  cinder  and  converter  slag.  Basic 
slag,  from  the  Thomas  Bessemer  Piocess,  which  often  contains 
a  high  per  cent,  of  phosphoric  acid,  requires  that  the  process  be 
slightly  modified. 


METHOD  FOR   THE  COMPLETE  ANALYSIS  OF  LEAD 
AND  COPPER  SLAGS,  MATTES  AND  CINDERS. 

Treat  1.5  grams  of  the  pulverized  material  with  about  20  c.c. 
of  hydrochloric  acid,  (sp.  gr.  1.2),  a  few  drops  of  concentrated 
nitric  acid  and  about  2  c.c.  of  concentrated  sulphuric  acid  in 
a  casserole.  Evaporate  until  heavy  white  fumes  of  sulphuric  an- 
hydride are  evolved.  Cool  and  add  about  25  c.c.  of  water.  Heat 
for  some  time  and  again  cool.  Filter  off  the  SiO0,  BaSO4  and 
PbSO4.  Wash  with  dilute  sulphuric  acid  (i  vol.  of  concentrated 
acid  to  20  vol.  of  water)  by  decantation,  leaving  as  much  as  pos- 


METALLURGICAL  ANALYSIS  17 

sible  of  the  residue  in  the  casserole.     Set  the  filtrate  aside  for  the 
determination  of  Fe,  Al,  Cu,  Zn,  Mn,  Ca  and  Mg. 

Digest  the  residue  in  the  casserole  with  a  strong  solution  of 
ammonium  acetate,  to  dissolve  the  lead  sulphate,  and  filter  on 
the  filter  used  in  the  first  operation.  Wash  with  hot  water  con- 
taining a  little  ammonium  acetate.  Ignite  the  residue  of  SiO2 
and  BaSO4,  cool  and  weigh  in  a  platinum  crucible.  Separate 
and  determine  the  SiO2  and  BaSO4  by  either  of  the  following 
methods : 

(a)  To  the  residue  in  the  crucible  add  4  or  5  drops  of  dilute 
sulphuric  acid,  and  add  i  or  2,  c.c.  of  hydrofluoric  acid  and  evap- 
orate under  the  hood  to  expel  the  silica  as  SiF4.  Ignite  and  weigh 
the  residue  of  BaSO4  and  calculate  BaO.     The  weight  of  barium 
sulphate    subtracted    from    the    weight    of   barium    sulphate   plus 
silica  gives  weight  of  silica. 

(b)  Fuse  the  insoluble  residue  of  silica  and  barium  sulphate 
with  3  or  4  grams  of  sodium  carbonate.     Dissolve  the  fused  mass 
in  hot  water  and  boil.     Filter  and  wash  with  hot  water  until  the 
washings  are  free  from  sulphates.     Acidify  the  filtrate  with  hy- 
drochloric acid  and  evaporate  to  dryness  and  determine  the  SiO2 
in  the  usual  manner.     Dissolve  the  precipitate  on  the  filter  paper 
in  dilute  hydrochloric  acid,  wash  the  filtter  with  hot  water,  heat 
the  solution  to  boiling  and  precipitate  the  barium  by  adding  dilute 
sulphuric   acid.     Allow  to  stand  for  some  time,  filter,   wash  and 
ignite.     Weigh  BaSO4. 

Determine  the  lead  by  either  of  the  following  methods : 

(a)  To  the  filtrate  containing  the  lead  acetate  add  acetic  acid 
to  acid  reaction,  dilute  with  water  to  250  c.c.,  heat  to  boiling  and 
titrate  with  standard  ammonium  molybdate  solution,  using  tannin 
(i  to  300)  for  indicator.    See  page,  8. 

(b)  To  the  filtrate  containing  the  lead  acetate  add  sulphuric 
acid,  allow  to  stand  for  a  short  time  and  filter  off  the  lead  sulphate. 
Wash  at  first  with  dilute  sulphuric  acid   (i   vol.   of  con.  H2SO4 
to  20  vol.  water)  and  then  with  alcohol  to  displace  the  sulphuric 
acid.     Dry,  ignite  and  weigh  the  PbSO4  in  a  porcelain  crucible. 
Calculate  the  per  cent,  of  lead. 

To  the  filtrate  containing  the  Cu,  Fe,  Al,  etc.,  add  a  little 
L/drochloric  acid,  heat  to  about  70°  and  precipitate  the  copper 
as  copper  sulphide  with  H2S.  Filter,  wash  with  hydrogen  sul- 


18  METALLURGICAL  ANALYSIS 

phide  water,  dry,  transfer  the  precipitate  to  a  weighed  Rose 
crucible,  burn  the  filter,  add  the  ash  to  the  contents  of  the  cru- 
cible. %Add  a  little  sulphur,  ignite  in  a  current  of  hydrogen  or 
coal  gas.  Allow  the  crucible  and  contents  to  cool  in  a  current 
of  the  gas,  and  weigh  as  Cu0S.  Calculate  per  cent,  of  copper. 

Instead  of  weighing  as  Cu2S,  the  precipitate  may  be  placed 
in  a  beaker,  the  filter  ash  added,  and  the  precipitate  dissolved 
in  nitric  acid,  when  the  copper  may  be  determined  electrically, 
colorimetrically  or  by  the  volumetric  method. 

Boil  the  filtrate  from  the  CuS  to  expel  all  the  hydrogen  sul- 
phide, filter  if  necessary,  add  a  little  concentrated  nitric  acid  and 
boil  for  a  short  time,  to  oxidize  the  iron.  Cool,  add  sodium  car- 
bonate until  the  solution  is  nearly  neutral.  Add  about  5  grams 
of  sodium  or  ammonium  acetate  and  then  about  a  half  liter  of 
hot  water,  heat  to  boiling  and  boil  for  two  or  three  minutes.  Al- 
low to  settle  for  a  few  moments.  Filter  while  hot  and  wash  with 
hot  water  by  decantation.  Dissolve  the  precipitate  in  hot  dilute 
hydrochloric  acid,  add  a  little  water,  heat  to  boiling,  add  ammonia 
in  slight  excess,  filter  and  wash  with  hot  water.  Dissolve  this  pre- 
cipitate of  iron,  alumina  (and  P2O5)  in  hydrochloric  acid  and 
dilute  with  water  to  250  c.c.  Take  100  c.c.  of  the  250  for 
volumetric  determination  of  iron.  Take  another  100  c.c.  and  pre- 
cipitate the  iron,  aluminum  and  phosphorus  with  ammonia.  Filter, 
wash  and  ignite  and  weigh  Fe2O3,  A12O3,  P2O5. 

Combine  the  filtrate  from  the  basic  acetate  precipitation  with 
the  filtrate  from  the  first  ammonia  precipitation,  acidify  with  acetic 
acid  and  boil.  Conduct  into  the  boiling  solution  a  current  of  hy- 
drogen sulphide  for  half  an  hour.  Filter  off  the  precipitate  of 
ZnS  and  wash  with  water,  containing  hydrogen  sulphide. 

If  the  precipitate  of  zinc  sulphide  is  not  very  large  it  may 
be  dried  and  ignited  in  a  porcelain  crucible,  with  the  addition  of 
a  little  ammonium  carbonate  to  assist  in  the  conversion  of  the 
zinc  sulphide  into  zinc  oxide,  cooled  and  weighed  as  ZnO. 

If  the  precipitate  of  zinc  sulphide  is  quite  large  dissolve  it  in 
hot  dilute  hydrochloric  acid  and  precipitate  the  zinc  as  basic 
carbonate  of  zinc  with  sodium  carbonate  added  in  excess  and 
the  solution  boiled.  Filter,  wash,  dry,  ignite  in  a  porcelain  cru- 
cible and  weigh  as  zinc  oxide.  Calculate  the  per  cent,  of  zinc. 

Boil  the  filtrate  from  the  precipitate  of  zinc  sulphide  with  an 


METALLURGICAL  ANALYSIS  19 

excess  of  bromine  water  for  about  half  an  hour.  Add  ammonia 
to  alkaline  reaction  and  a  little  more  bromine  water  and  heat 
the  solution  just  below  boiling  until  the  precipitate  is  brown  col- 
ored and  flaky,  and  the  solution  colorless.  Filter  off  the  pre- 
cipitated hydrated  peroxide  of  manganese,  MnO  (OH)0,  wash 
thoroughly  with  hot  water,  test  filtrate  for  manganese  with  more, 
bromine  and  ammonia,  heat  for  some  time  and  filter  if  necessary, 
dry,  ignite  and  weigh  Mn^O  .  Calculate  the  per  cent,  of  manganese. 

Instead  of  igniting  the  manganese  precipitate,  it  may  be 
transferred  to  a  beaker  and  determined  by  the  Williams  method. 
See  page  30. 

See  also  methods  for  the  determination  of  manganese  in 
blast  furnace  slag,  page  15. 

In  the  filtrate  from  the  manganese  determine  the  calcium  and 
magnesium  in  the  usual  manner. 

Determination  of  Sulphur — Take  a  separate  portion  using  the 
method  described  on  page  31. 


COAL  AND  COKE  ANALYSIS. 

Pulverize  10  to  15  grams  of  the  carefully  sampled  coal  and 
transfer  it  to  a  tightly  corked  bottle. 

Moisture — Dry  one  gram  of  the  pulverized  coal  in  an  open 
porcelain  or  platinum  crucible  at  104°- 107°  for  one  hour.  Cool 
in  a  desiccator  and  weigh  Covered. 

Volatile  Combustible  Matter — Place  one  gram  of  the  fresh, 
undried,  powdered  coal  in  a  platinum  crucible  weighing  twenty 
or  thirty  grams  and  having  a  tightly  fitting  cover.  Heat  over  the 
full  flame  of  the  Bunsen  burner  for  seven  minutes.  Cool  and 
weigh.  To  find  volatile  combustible  matter,  subtract  the  per  cent, 
of  moisture  from  the  loss  found  here. 

Ash — Burn  the  portion  of  the  powdered  coal  used  for  the  de- 
termination of  moisture,  at  first  over  a  very  low  flame,  with  the 
crucible  open  and  inclined  till  free  from  carbon.  Cool  and  weigh. 
Examine  the  ash  for  unburned  carbon  by  moistening  it  with 
alcohol. 

Fixed  Carbon — This  is  found  by  subtracting  the  per  cent,  of 
ash  from  the  per  cent,  of  coke  as  found  above. 


20  METALLURGICAL  ANALYSIS 

Sulphur — Eschka's  Method — Mix  thoroughly  one  gram  of  the 
finely  powdered  coal  with  one  gram  of  magnesium  oxide,  and  one 
half  gram  of  dry  sodium  carbonate,  in  a  thin  platinum  dish  having 
a  capacity  of  75  c.c.-ioo  c.c.  The  dish  is  heated  on  a  triangle 
over  an  alcohol  lamp,  held  in  the  hand  at  first.  Gas  must  not  be 
used  on  account  of  the  sulphur  it  contains.  The  mixture  is  fre- 
quently stirred  with  a  platinum  wire  and  the  heat  raised  very 
slowly,  especially  with  soft  coals.  The  flame  is  kept  in  motion 
and  barely  touching  the  dish,  at  first,  till  strong  glowing  has 
ceased,  and  is  then  increased  gradually  till  in  15  minutes  the 
bottom  of  the  dish  is  at  a  low  red  heat.  When  the  carbon  is 
burned  transfer  the  mass  to  a  beaker  and  rinse  the  dish,  using 
about  50  c.c.  of  water.  Add  15  c.c.  of  saturated  bromine  water 
and  boil  for  5  minutes.  Allow  to  settle,  decant  through  a  filter. 
Boil  a  second  and  third  time  with  30  c.c.  of  water  and  wash 
till  the  filtrate  gives  only  a  slight  opalescence  with  silver  nitrate 
and  nitric  acid.  The  volume  of  the  filtrate  should  be  about  200 
c.c.  Add  one  and  a  half  cubic  centimeters  of  concentrated  hydro- 
chloric acid.  Boil  till  the  bromine  is  expelled  and  add  to  the  hot 
solution,  drop  by  drop,  especially  at  first,  and  with  constant  stir- 
ring 50  c.c.  of  a  2  per  cent,  solution  of  hot  barium  chloride, 
Digest  oh  a  water  bath  until  the  precipitate  settles.  Filter,  wash, 
ignite,  cool  and  weigh  BaSO4  and  calculate  the  per  cent,  of 
sulphur. 

Note — For  practical  purposes  the  sulphur  may  be  considered 
as  existing  in  the  coal  in  the  form  of  pyrites,  and  that  in  the 
above  analysis  one-half  of  the  sulphur  passes  off  with  the  volatile 
combustible  matter  and  the  other  half  with  the  fixed  carbon. 

In  calculating  results  of  analysis,  one-half  of  the  sulphur  may 
be  subtracted  from  the  volatile  matter  and  the  other  one-half 
from  the  fixed  carbon.  If  a  determination  of  phosphorus  is  de- 
sired, it  may  be  found  in  the  ash  after  burning  the  coal  or  coke 
and  can  be  determined  by  any  of  the  well  known  methods  and 
the  per  cent,  deducted  from  the  per  cent,  of  ash. 

If  the  calculations  are  made  as  indicated  above,  the  sum  total 
of  moisture,  volatile  matter,  fixed  carbon,  ash,  sulphur  and  phos- 
phorus should  equal  one  hundred  per  cent. 

Reference  : 

Jour.  Am.  Chem.  Soc.,  Vol.  XXI,  page  1116. 


METALLURGICAL   ANALYSIS  21 

DETERMINATION  OF  IRON  IN  IRON  ORES. 

Standardisation  of  Potassium  Permanganate  Solution: 

Dissolve  about  eight  grams  of  potassium  permanganate  crys- 
tals in  about  500  c.c.  of  water,  with  frequent  agitation  to  in- 
sure complete  solution,  if  possible.  After  this,  allow  the  solu- 
tion to  stand  for  two  or  three  days.  Filter  through  a  layer  of 
asbestos,  dilute  to  about  2000  c.c.  and  mix  thoroughly. 

Weigh  out  and  place  in  number  2  beakers  two  portions  of  stan- 
dard iron  ore  of  about  0.5  gram  each.  Pour  over  each  of  these 
10  c.c.  of  hydrchloric  acid  (sp.  gr.  1.2),  and  as  much  stannous 
chloride  solution  as  will  nearly  reduce  the  iron,  cover  the  beakers 
with  glass  covers,  heat  at  a  temperature  just  below  boiling  until 
the  undissolved  residue  is  white  or  nearly  so. 

The  stannous  chloride  solution  should  be  of  -such  strength 
that  about  3.5  c.  c.  will  reduce  one-half  gram  of  the  average  iron 
ore.  It  may  be  prepared  by  dissolving  pure  tin  in  hot  con- 
centrated hydrochloric  acid  leaving  an  excess  of  the  acid  and  then 
properly  diluting  with  distilled  water,  or 

By  dissolving  100  grams  of  stannous  chloride  salt  in  70  c.c. 
of  concentrated  hydrochloric  acid  and  diluting  with  distilled  water 
to  one  half  liter. 

If  a  dark  residue  remains,  collect  it  on  a  filter,  wash  free  from 
hydrochloric  acid,  and  ignite  the  filter  in  a  platinum  crucible. 
Mix  the  ash  with  a  small  amount  of  sodium  carbonate  and 
heat  to  fusion.  Cool  and  dissolve  the  fused  mass  in  boiling 
water  in  the  crucible.  Unite  solution  and  precipitate  (if  any) 
with  the  acid  extraction.  Heat  the  solution  then  to  boiling, 
wash  off  the  cover  and  sides  of  the  beaker  and  add  stannous 
chloride  solution  to  the  hot  solution  until  it  is  colorless,  but 
avoid  adding  more  than  a  drop  or  two  in  excess.  In  case  a 
larger  amount  has  been  added,  add  permanganate  solution  until 
a  tinge  of  ferric  iron  is  produced.  Destroy  this  as  above. 
Dilute  with  100  c.c.  of  water  and  cool  completely;  when  cold 
add  rapidly  about  30  c.c.  of  mercuric  chloride  solution  (50  grama 
per  liter).  Allow  the  solution  to  stand  3  minutes,  dilute  with 
water  to  about  300  c.c. 

Next  add  about  10  c.c.  of  a  solution  prepared  as  follows : 
160  grams  of  manganous  sulphate  dissolved  in  1750  c.c.  of  water, 
to  which  is  added  330  c.c.  of  phosphoric  acid  syrup  (sp.  gr.  1.7) 
and  320  c.c.  of  concentrated  sulphuric  acid. 


22  METALLURGICAL  ANALYSIS 

Titrate  the  solution  as  quickly  as  possible  with  the  potassium 
permanganate  to  the  appearance  of  a  faint  pink  color,  which  re- 
mains permanent  for  a  short  time.  The  reaction  for  the  oxida- 
tion of  the  iron  from  ferrous  sulphate  to  ferric  sulphate  by  the 
permanganate  in  presence  of  sulphuric  acid  is  as  follows  : 
ioFeSO4+2KMnO4-j-8H2SO4— 

5Fe2(SO4).{+K2SO4-f2MnSO4-i-8H0O. 

Calculate  the  strength  of  the  permanganate  in  terms  of  metallic 
iron. 

Standardisation  of  Potassium  Bichromate  Solution  : 

Dissolve  about  12  grams  of  potassium  bichromate  in  approxi- 
mately 2000  c.c.  of  water.  Mix  thoroughly  and  standardize  by 
means  of  standard  iron  ore.  Decompose  and  reduce  the  ore  just 
the  same  as  in  the  standardization  of  permanganate  solution.  Omit 
the  addition  of  the  manganous  sulphate  mixture.  Titrate  the  re- 
duced iron  solution  with  the  potassium  bichromate  solution.  The 
reaction  is : 

6FeCl2+K2Cr2O_+i4HCl=6FeCl3+2C+Cl3+2KCl+7HoO. 
The  end  point  in  the  titration  is  reached  when  a  drop  or  two  of 
the  iron  solution  and  a  drop  of  very  weak  solution  of  freshly  pre- 
pared potassium  ferricyanide  gives  no  blue  color  when  brought  to- 
gether on  a  porcelain  tile.     Reaction  : 

3FeCl2-f2K3Fe(CN)(5^Fe3Fe2(CN)12+6KCl. 
Calculate   the   strength   of   the   potassium   bichromate   solution 
in  terms  of  metallic  iron. 

It  is  advantageous,  when  one  has  a  great  many  determinations 
of  iron  to  make  to  dilute  the  standard  solution  so  that  each  c.c.  is 
equivalent  to  one  per  cent,  or  two  per  cent,  of  metallic  iron,  when 
0.5  gram  is  taken  for  analysis.  E.g.,  suppose  it  is  desired  to  have 
a  permanganate  solution  of  such  a  strength  that  each  c.c.  will 
represent  I  per  cent,  of  metallfc  iron  when  0.5  gram  is  taken. 

The  calculation  is  as  follows : 
ioFeSO4+2KMnO4+8H0SO4= 

~5Fe0  ( SO4)  r+K0SO4+2MnSO4-f  8H.,O. 
loFe    :    2KMnO4  —  .005    :     x  or 
560     :  316  —  .005    :    x 

x  =   .002811  grams  KMnO4  per  c.c. 
.002821  x  100  =  2.821  grams  of  KMnO4  per  liter. 


METALLURGICAL  ANALYSIS  23 

StilJ  another  practice  in  commercial  work  is  to  weigh  out  the 
ore  in  such  proportions,  that  the  burette  readings  of  the  standard 
solution  give  the  percentage  at  once  without  calculation.  Thus,  if 
the  standard  ore  contains  64.43  per  cent,  iron,  the  weight  of  ore 
would  be  so  taken  that  the  readings  of  the  burette  would  be 
32:215  c.c.  If,  however,  it  should  be  so  taken  that  the  reading  is 
32.8  c.c.,  then  the  weight  would  be  diminished  in  the  proportion  ot 
32.215  to  32.8.  For  the  obtaining  of  the  percentage  the  burette 
reading  is  doubled. 

The  Process; 

Pulverize  the  ore  in  an  agate  mortar  to  a  fine  powder.  If  nec- 
essary dry  the  ore  in  a  drying  oven  until  its  weight  is  constant. 
Weigh  out  duplicate  samples  of  0.5  gram  each.  Place  each  sample 
in  a  number  2  beaker  and  add  10  c.c.  of  hydrochloric  acid  (sp.  gr. 
1.2)  and  heat  on  the  iron  plate.  If  the  ore  contains  organic  matter 
add  a  little  potassium  chlorate  and  boil  till  the  smell  of  liberated 
chlorine  has  disappeared.  Add  stannous  chloride  and  continue  as 
in  the  standardization  of  the  permanganate  solution  with  standard 
iron  ore.  Or,  if  it  is  desired  to  use  the  bichromate  method,  continue 
as  in  the  standardization  of  potassium  bichromate  with  standard 
iron  ore.  Two  results  on  the  same  sample  should  agree  within 
o.i  per  cent. 

References  : 

K.    W.    Mahon,   Am.    Chem.   Jour.,   Vol.    XV.    page   360. 
Jour.  Am.   Chem.  Koc.,  Vol.  XVII,  page  405. 
Jour.  An.  &  App.  Chem..,  Vol.  V,  page  325. 

DETERMINATION  OF  PHOSPHORUS  IN  IRON  ORES. 

EMMERTON'S  VOLUMETRIC  METHOD — Dissolve  3  grams  of  the  pul- 
verized ore  in  40  c.c.  of  concentrated  hydrochloric  acid,  and  evap- 
orate to  about  20  c.c..  avoiding  a  temperature  so  high  as  to  con- 
vert the  ferric  chloride  into  ferric  oxide.  Add  10  c.c.  of  concen- 
trated nitric  acid  and  evaporate  down  to  about  10  c.c.  If  the  nitric 
acid  solution  is  allowed  to  go  to  dryness,  it  affords  ferric  oxide, 
insoluble  in  nitric  acid,  which  always  retains  some  phosphate. 
This  can  only  be  brought  into  solution  by  hydrochloric  acid,  which 
must  be  removed  by  addition  of  more  nitric  acid  and  evaporating. 
Dilute  with  about  20  c.c.  of  distilled  water  and  filter  into  an  Erlen- 
meyer  flask  of  about  400  c.c.  capacity  and  wash  with  the  least  pos- 


24  METALLURGICAL  ANALYSIS 

sible  amount  of  water.  It  is  not  always  possible  to  get  the  whole 
of  the  phosphorus  in  solution  by  the  above  process,  therefore  the 
residue  should  be  treated  by  one  of  the  following  methods  in  order 
to  obtain  any  insoluble  phosphorus  which  may  be  present. 

(a)  Ignite  the  residue  in  a  platinum  crucible,  fuse  it  with  5  to 
6  parts   of  sodium  carbonate,   dissolve   the   fused  mass   in   water 
and  hydrochloric  acid,  evaporate  to  dryness  in  order  to  dehydrate 
any  silicic  acid  that  may  be  present.     Moisten  the  residue  with 
concentrated  nitric  acid,  heat  after  adding  a  small  amount  of  water, 
and  filter  into  the  flask  containing  the  soluble  phosphorus,  (or  into 
another  flask  if  it  is  to  be  determined  separately). 

(b)  Ignite  the  residue  in  a  platinum  crucible,  add  3  or  4  drops 
of  dilute  sulphuric  acid  and  about  5  c.c.  of  hydrofluoric  acid,  and 
evaporate  under  the  hood  to  complete  dryness  and  finally  ignite  to 
redness.     Fuse  the  residue  with  5  to  6  parts  of  sodium  carbonate, 
dissolve  the  fused  mass  in  water  and  nitric  acid  and  add  it  to  the 
solution  in  the  flask  containing  the  soluble  phosphorus. 

(c)  Place  residue  and  filter  paper  in  a  platinum  crucible  and 
ignite.    When  the  paper  is  burned  off  break  up  the  residue  with  a 
platinum  rod  and  ignite  at  a  red  heat  for  about  two  minutes.     Pul- 
verize the  ignited  residue  in  an  agate  mortar.     Transfer  the  resi- 
due to  beaker,  add  water  and  a  little  nitric  acid  and  boil  gently 
for  about  5  minutes.     Filter  into  the  flask  containing  the  soluble 
phosphorus. 

To  the  solution  add  ammonia,  shaking  the  flask  after  each 
addition,  until  the  mass  sets  to  a  stiff  jelly.  Then  add  strong  nitric 
acid  gradually,  shaking  well  after  each  addition,  until  the  precipi- 
tate dissolves  and  then  add  a  little  in  excess  to  get  a  clear  amber 
color.  The  solution  at  this  point  should  be  about  200  to  250  c.c. 
in  bulk.  Put  a  thermometer  into,  the  liquid  and  heat  carefully  un- 
til the  temperature  reaches  8s°C.  Add  at  once  50  c.c.  of  ammonium 
molybdate  solution  to  precipitate  the  phosphorus  as  phosphomo- 
lybdate  of  ammonium,  (NH4)3PO4,  i2MoO3,  I2H2O.  Close  the 
flask  with  a  rubber  stopper,  wrap  it  in  a  thick  cloth  or  towel  and 
shake  or  whirl  for  five  minutes,  then  allow  to  stand  for  five  min- 
utes for  the  precipitate  to  settle.  Filter  and  wash  the  precipitate 
five  times  with  water  containing  10  c.c.  concentrated  nitric  acid 
per  liter  and  then  five  times  with  water,  containing  ten  grams  of 
potassium  nitrate  per  liter.  Put  the  funnel  containing  the  yellow 


METALLURGICAL  ANALYSIS 


25 


precipitate   in  the   neck   of  a  flask  of  about  400  c.c.   capacity  in 
which  has  been  placed  15  grams  of  granulated  zinc. 

Pour  over  the  precipitate  on  the  filter  dilute  ammonia  (one  vol. 
ammonia,  sp.  gr.  .96,  and  three  volumes  of  water)  and  receive  the 
solution  in  the  flask  containing  the  granulated  zinc.  Next  pour 
into  the  flask  100  c.c.  of  dilute  sulphuric  acid  (i  vol.  acid  to  5  vol. 
of  water)  and  heat  on  the  iron  plate  for  about  15  minutes.  The 
rolor  of  the  solution  passes  through  pink,  plum,  pale  olive  green  to 
dark  green.  The  MoOg  is  reduced  by  the  zinc  and  sulphuric  acid 
to  a  mixture  of  oxides  corresponding  to  the  formula  Mo24OS7, 
Filter  through  a  folded  filter.  The  zinc  is  decanted  on  to  the  filter 
paper  with  the  liquid  to  keep  up  the  reducing  action.  Wash  two  or 
three  times  with  water.  Titrate  with  standard  potassium  perman- 
ganate solution,  to  the  appearance  of  the  pink  color  due  to  the 
slight  excess  of  permanganate.  The  reaction  is  : 


The  strength  of  the  permanganate  solution  in  terms  of  MoO3  is 
'88.  1  6  per  cent,  of  its  strength  against  iron.  The  yellow  precipi- 
tate of  phosphomolybdate  of  ammonium  contains  i2MoO3  to  i  of 
P,  the  phosphorus  being  1.794  Per  cent,  of  the  MoOg.  Therefore 
88.16%  of  the  strength  of  the  solution  in  terms  of  iron  gives  its 
strength  in  terms  of  MoOs  and  1.794%  of  this  gives  its  strength  in 
terms  of  phosphorus. 

Let  Fe=the  iron  value  of  the  permanganate. 

Let  P'—  phosphorus  value. 

ThenP=Fe  X  .015816. 

Two  results  on  the  same  sample  should  agree  within  .001%. 
It  is  advisable  to  check  the  strength  of  the  standard  perman- 
ganate in  terms  of  phosphorus  as  calculated  above  by  means  of  a 
standard  iron  ore  of  known  phosphorus  content,  or  by  means  of 
some  of  the  pure  yellow  precipitate  dried  at  uo°C.  It  contains 
1.63  per  cent,  phosphorus. 

Emmerton,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  XV,  page  93. 
Dudley  &  Pease,  Jour.  Am.  Chem.  Soc.,  Vol.  XVI,  page  224. 
Blair  &  Whitfield,  Jour.  Am.  Chem.  Soc.,  Vol.  XVII,  page  747. 
G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.  XVIII,  page  955. 
W.  A.  Noyes,  Jour.  Am.  Chem.  Soc.,  Vol..  XVI,  page  553. 
W.  A.  Noyes,  Jour.  Am.  Chem.  Soc.,  Vol.  XVII,  page  129. 
Mixter  &  Du  Bois,  Jour.  Am.  Chem.  Soc.,  Vol.  XIX,  page  614. 
H.  C.  Babbitt,  Jour.  Am.  Chem.  Soc..  Vol.  VII,  page  165. 
E.  D.  Campbell,  Jour.  Am.  Chem.  Soc.,  Vol.  VII,  page  2. 
Dudley  &  Pease,  Jour.  Am.  Chem.  Soc.,  Vol.  VII,  page  519. 
P.  W.  Shimer,  Jour.  Am.  Chem.  Soc.,   Vol.  XXI,  page  723. 


26  METALLURGICAL  ANALYSIS 

Reduction  of  the  MoO^in  a  Reductor: 

Obtain  the  yellow  precipitate  and  dissolve  it  in  ammonia  just 
as  described  on  page  25  and  the  solution  is  allowed  to  run  into  a 
clean  beaker.  Wash  the  filter  paper  with  water  until  the  solution 
measures  about  60-70  c.c.  Add  to  the  liquid  in  the  beaker  10  c.c. 
concentrated  sulphuric  acid  and  pass  it  through  the  reductor  which 
has  just  been  cleaned  by  passing  through  it  distilled  water  and 
then  loo  c.c.  of  warm  dilute  sulphuric  acid,  strength  :  25  c.c.  con- 
centrated sulphuric  acid  per  liter  of  distilled  water.  After  passing 
the  molybdate  solution  through  the  reductor,  wash  with  about  200 
c.c.  of  the  warm  dilute  sulphuric  acid,  and  finally  with  about  50  c.c. 
hot  water. 

References  : 

Jones'  Reductor,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  XVII,  page  441 
Dudley  &  Pease,  Jour.  An.  &  App.  CJiem.,  Vol.  VII,  page  109. 

Acidimetric  Method — Follow  Emmerton's  method  until  the  yel- 
low precipitate  of  ammonio-phospho-molybdate  is  obtained  and 
then  continue  as  follows :  Filter  the  yellow  precipitate  on  a  9  c.m. 
filter  and  wash  by  decantation  with  water  containing  10  c.c.  con- 
centrated nitric  acid  per  liter  and  then  five  times  with  water  con- 
taining 10  grams  potassium  nitrate  per  liter.  Place  precipitate 
and  filter  in  the  flask  containing  the  bulk  of  the  precipitate.  Dis- 
solve the  precipitate  in  an  excess  of  standard  solution  of  caustic 
soda  or  caustic  potash.  With  potash  the  reaction  is : 

2(NH4)  3P04+24MoOa+46KOH+H20= 

(NH4)4H2P208H-(NH4)2Mo04+23K2Mo04+23H20. 

Add  water  and  a  few  drops  (.5  c.c.)  of  phenol  phthalein  indicator 
and  titrate  the  excess  of  caustic  alkali  with  a  standard  solution 
of  nitric  acid. 

Solutions  Required: 

Standard  Caustic  Potash— Strength,  8.3334  grams  of  potassium 
hydroxide  per  liter.  This  solution  may  be  prepared  from  nor- 
mal caustic  potash  solution  by  taking  148.39  c.c.  and  diluting  to 
one  liter  with  distilled  water.  One  cubic  centimeter  of  this  solu- 
tion will  equal  .0002  gram  of  phosphorus. 

Standard  Caustic  Soda—  Strength,  5.9355  grams  of  sodium  hy- 
droxide per  liter.  This  solution  can  be  prepared  from  normal 


METALLURGICAL  ANALYSIS  27 

caustic  soda  by  diluting  148.39  c.c.  to  one  liter.     This  solution  is 
of  such  a  strength  that  one  c.c.  equals  .0002  gram  phosphorus. 

Standard  Nitric  Acid — This  solution  has  the  same  strength, 
volume  for  volume,  as  the  caustic  soda  or  caustic  potash.  It  can 
be  prepared  by  diluting  148.39  c.c.  of  normal  nitric  acid  to  one 
liter.  It  contains  9.3484  grams  of  nitric  acid  to  the  liter. 

Phenol  Phthalein — One  gram  dissolved  in  100  c.c.  of  60% 
alcohol. 

Calculation  of  Analysis — The  difference  between  the  number  of 
c.c.  of  caustic  alkali  used  and  the  number  of  c.c.  of  standard  acid 
multiplied  by  .0002  gives  the  weight  of  phosphorus  found. 

Weight  of  Phosphorus   X    100 

-  =  per  cent,  phosphorus. 
Amount  of  ore  taken  . 

It  is  advisable  to  check  the  strength  of  the  standard  acid  and 
alkali  in  terms  of  phosphorus  as  calculated  above,  against  a  stan- 
dard iron  ore  of  known  phosphorus  content,  or  by  means  of  some 
of  the  pure  yellow  precipitate  dried  at  no°C.  It  contains  1.63 
per  cent,  phosphorus. 

References  : 

J.  O.  Handy,  Jour.  An.  d  App.  Chem.,  Vol.  VI,  page  204. 
Manby,  Jour.  An.  d  App.  Chem.,  Vol.  VI,  page  82. 
M.  Rothberg,  Jour.  An.  &  App.  Chem.,  Vol.  VI,  page  241. 
F.  Hundeshagen,  Zeit.  Anal.  Chem.,  Vol.  XXV,  page  489. 

Wood's  Method — Direct  weighing  of  the  phosphomolybdate  of 
ammonium. 

Follow  Emmerton's  method  until  the  yellow  precipitate  is  ob- 
tained then  filter  on  a  9  c.m.  filter  which  has  been  previously  dried 
at  uo°C.  and  weighed.  Wash  with  a  two  per  cent,  nitric  acid 
solution  until  free  from  iron,  then  wash  once  or  twice  with  alco- 
hol. Dry  in  the  air  bath  at  110°  C.  and  weigh.  1.63  per  cent  of 
the  dried  precipitate  is  phosphorus. 

Note — The  yellow  precipitate  must  contain  no  silica.  With  ores 
containing  soluble  silicates,  evaporate  the  acid  solution  to  com- 
plete dryness,  to  render  the  silica  insoluble,  moisten  with  hydro- 
chloric acid,  add  water,  heat,  and  filter  off  the  insoluble  residue.. 

Reference  :  E.  F.  Wood,  Zeit.  Anal.  Chem.,  Vol.  XXVIII,  pages  141- 
172. 


28  METALLURGICAL  ANALYSIS 

DETERMINATION  OF  MANGANESE  IN  IRON  ORES. 

VOLHARD'S  METHOD,  MODIFIED  BY  G.  C.  STONE  —  Grind  the  ore 
to  a  fine  powder.  Weigh  out  two  portions  of  about  one  gram  each 
and  place  in  number  2  beakers.  Pour  into  each  10  c.c.  of  concen- 
trated hydrochloric  acid.  Cover  the  beakers  with  glass  covers 
and  heat  until  ore  is  decomposed.  Add  a  little  potassium  chlorate 
and  boil  a  minute  or  two.  Remove  covers  and  evaporate  off  ex- 
cess of  acid.  Cool  and  add  cold  water.  At  this  point  if  there  is 
any  doubt  as  to  the  decomposition  of  the  ore,  filter  off  and  test 
insoluble  residue  for  manganese.  If  not,  the  filtration  may  be 
omitted.  Wash  contents  of  the  beaker  into  a  half  liter  flask  with 
cold  water.  Nearly  neutralize  with  carbonate  of  soda;  the  solu- 
tion should  remain  clear  and  should  be  of  a  deep  red  color.  Next 
add  an  emulsion  of  zinc  oxide  until  the  precipitate  curdles  and  set- 
tles readily.  Add  a  little  more  of  the  emulsion  to  make  sure  that 
the  precipitation  is  complete.  The  reaction  is  : 


Dilute  to  the  mark  with  cold  water,  mix  thoroughly,  pour  into  a 
beaker  and  allow  the  precipitate  to  settle.  Take  portions  of  200 
cc.  each  of  the  supernatant  liquid  and  transfer  to  400-500  c.c. 
flasks  ;  heat  nearly  to  boiling  and  titrate  one  after  the  other  with 
standard  potassium  ^permanganate  solution,  adding  it  in  small 
portions  at  a  time,  and  shaking  the  flask  over  a.Bunsen  flame,  after 
each  addition.  Keep  the  temperature  as  near  the  boiling  point  as 
possible,  while  making  the  titration.  The  greater  part  of  the  per- 
manganate solution  should  be  added  at  once  and  the  solution  vig- 
orously shaken  and  then  the  precipitate  allowed  to  settle.  The  fol- 
lowing is  the  reaction  which  takes  place  : 

4KMnO4+6MnCl0-f4H9O=ioMnO2-f4KCl+8HCl. 
In  the  above  equation  we  see  that  two  molecules  of  potassium  per- 
manganate oxidizes  three  molecules  of  manganous  chloride,  while 
in  the  following  equation  : 
2KMnO4-f-ioFeSO4-f-8H2SO4= 

5Fe2  (  S04)  3+K2S04-f2MnS04+8H20 

we  see  that  two  molecules  of  potassium  permanganate  oxydizes 
ten  molecules  of  ferrous  sulphate,  therefore  the  oxydizing  power 
of  KMnO4  in  the  former  case  is  only  3/10  as  great  as  in  the  latter. 


METALLURGICAL  ANALYSIS 


29 


So  the  value  of  the  permanganate  in  terms  of  manganese  is  to 
its  value  in  terms  of  iron. as  3  :  10  or  55/56  X  V10  =  165/56<r  ^he 
value  of  the  standard  permanganate  solution  in  terms  of  iron  mul- 
tiplied by  1GVr,60  gives  strength  of  permanganate  solution  in  terms 
of  manganese. 

References  : 

Jour.  Am.  Chem.  Soc.,  Vol.  XVIII,  page  385. 

Liebeg's  Annalen,  197,  page  318. 

Chem.  News,  Vol.  XL,  page  207. 

G.  C.  Stone,  Jour.  Am.  Chem.  Soc.,  Vol.  XVIII,  page  228. 

G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.  XVIII,  page  498. 

FORD- WILLIAMS  METHOD — This  is  a  good  method  to  use  when 
the  ore  contains  only  a  small  amount  of  manganese. 

Pulverize  the  ore  to  a  fine  powder.  Weigh  out  duplicate  sam- 
ples of  one  to  five  grams  each.  With  ores  high  in  manganese  use 
one  gram;  with  ores  low  in  manganese  weigh  about  five  grams. 
Place  each  sample  in  a  number  4  beaker,  add  10  c.c.  concentrated 
hydrochloric  acid  for  each  gram  of  ore  taken.  Cover  the  beaker 
and  heat  on  the  iron  plate  until  the  residue  is  white  or  nearly  so. 
Then  add  25  to  50  c.c.  strong  nitric  a'cid  and  boil  about  five  min- 
utes to  expel  hydrochloric  acid.  If  there  is  a  large  insoluble  resi- 
due, filter  it  on  an  asbestos  filter  and  wash  with  strong  nitric  acid. 
If  the  insoluble  residue  is  small,  the  filtration  may  be  omitted. 

Now  add  75  c.c.  of  strong  nitric  acid  and  heat.  When  the 
solution  is  warm  add  about  5  grams  of  potassium  chlorate,  bring 
the  solution  to  a  boil  and  continue  the  boiling  about  10  minutes. 
If  the  sample  contains  much  silica,  add  a  few  drops  of  hydro- 
fluoric acid  (more  or  less  according  to  the  amount  of  silica  pres- 
ent) and  boil  for  a  few  minutes.  Allow  it  to  cool  somewhat,  add 
25  c.c.  more  nitric  acid  and  five  grams  more  of  potassium  chlorate 
and  again  boil  for  about  10  minutes.  If  the  nitric  acid  has  the 
faintest  yellow  color,  it  indicates  the  presence  of  nitrous  acid. 
Nitrous  acid  reduces  MnO2  to  MnO,  which  is  soluble.  This  acid 
may  be  removed  by  blowing  a  current  of  air  through  the  HNO3. 

Manganous  nitrate  in  the  strong  nitric  acid  solution  is,  by  a 
complex  reaction,  oxidized  to  insoluble  manganese  dioxide  on  the 
addition  of  potassium  chlorate.  The  following  is  probably  the 
reaction : 

2MnO-fN0O.  =2MnO0-f  N,O3. 


30  METALLURGICAL  ANALYSIS 

Cool  the  solution  quickly  and  filter  on  an  asbestos  filter,  using 
a  filter  pump.  Wash  two  or  three  times  with  strong  nitric  acid, 
suck  the  precipitate  as  dry  as  possible  and  then  wash  two  or  three 
times  with  cold  water  to  rid  of  all  the  nitric  acid.  Transfer  the  pre- 
cipitate with  the  asbestos  filter  to  the  beaker  in  which  the  precipi- 
tation was  made.  Measure  into  the  beaker  100  c.c.  of  a  standard 
solution  of  ferrous  sulphate  prepared  as  follows : 

10  grams  of  crystallized  salt.  FeSO4,  /H^O  in  900  c.c. 

water  and   100  c.c.   Con.    H0SO4,  thoroughly  mixed. 

The  reaction  between  the  precipitate  of  MnO,,  and  this  solution  is : 

MnOQ+2FeSO4+2H2SO4==MnSO4H-Fe~(SO4)34-2H.)O. 
Stir  until  the  whole  of  the  precipitate  has  been  dissolved.  Dilute 
the  solution  with  water  and  titrate  the  excess  of  ferrous  sulphate 
with  a  standard  potassium  permanganate  solution.  If  the  strength 
of  the  permanganate  solution  in  terms  of  iron  is  known,  its 
strength  in  terms  of  manganese  can  be  calculated  from  the  above 
reaction.  We  see  that  two  Fe  is  equivalent  to  one  Mn  and  we  can 
make  the  following  proportion : 

112:55  =  Strength  of  permanganate  in  terms  of  Fe    :  x 
x  —  Strength  of  permanganate  in  terms  of  Mn. 

Find  the  value  of  the  ferrous  sulphate  solution  in  terms  of  the 
permanganate  solution  by  taking  50  c.c.  of  the  ferrous  sulphate 
solution,  placing  it  in  a  beaker,  adding  water  and  titrating  to  a 
faint  pink  color  with  permanganate. 

Example: 

Amount  of  ore  taken  for  analysis,  2  grams. 

Strength  of  the  permanganate  in  terms  of  Mn,  .002  gram. 

50  c.c.  Ferrous  Sulphate  solution  =  15  c.c.  permanganate. 

Then  100  c.c  Ferrous  Sulphate  solution  =  30  c.c.  permanganate. 
After  treating  the  precipitate  of  MnO0  with  100  c.c.  of  ferrous 
sulphate  solution  it  required  10  c.c.  of  the  standard  permanganate 
solution  to  give  a  permanent  pink  color.  As  100  c.c.  of  the  fer- 
rous sulphate  solution  —  30  c.c.  of  the  permanganate  solution, 
there  would  be  the  equivalent  of  30 — 10  c.c.  or  20  c.c.  of  per- 
manganate in  ferrous  sulphate  oxydized  by  the  MnO0. 

One  c.c.  of  the  permanganate  being  equal  to  .002  gram  of  man- 


METALLURGICAL  ANALYSIS  31 

ganese,  20  c.c.  is  equal  to  .04  gram  Mn,  and  2  grams  of  the  sample 
having  been  taken 
.04  X  ioo 
—  2  per  cent,  manganese. 


References  : 

Ford,  Jour.  Am.  Chem.  Soc.,  Vol.  XX,  page  504. 
Ford,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  IX,  page  397. 

Julian's  modification  of  the  above  methods  is  as  follows  :  Ob- 
tain the  manganese  dioxide  precipitate  exactly  as  given  above ; 
when  the  manganese  is  all  oxidized  to  dioxide,  cool,  and  dilute 
to  400-450  c.c.  Now  add  from  a  burette  an  excess  of  standard 
hydrogen  peroxide,  to  completely  dissolve  the  precipitate.  The 
reaction  is : 

MnO()+H0O0+H0SO4  =  MnSO4+2H2O+O2. 
Immediately  titrate  the  excess  of  hydrogen  peroxide  with  a  stand- 
ard potassium  permanganate  solution.     The  reaction  is : 
2KMnO4+5H2O,+4H0SO4  =  2HKSO4+2MnSO4+ 8H9O-f5O0. 
The  hydrogen  peroxide  solution  is  prepared  by  thoroughly  mix- 
ing one  pound  of  hydrogen  peroxide  with  about  eight  liters   of 
water  and  ioo  c.c.  of  concentrated  sulphuric  acid.     It  is  standard- 
ized by  means  of  a  standard  potassium  permanganate  solution. 

References  : 

F.  Julian,  Jour.  Am.  Chem.  Soc.,  Vol.  VII,  page  113. 

F.  Julian,  Berg.  u.  Hiittcnmann  Keit.,  1897,  pages  56,  410. 

Jour.  Soc.  Chem.  Industry,  1898,  page  185. 


DETERMINATION  OF  SULPHUR  IN  IRON  ORES. 

Weigh  one  gram  of  the  finely  pulverized  ore  into  a  large 
platinum  crucible ;  add  about  eight  grams  of  chemically  pure 
carbonate  of  soda  and  about  one  half  gram  of  potassium  nitrate ; 
mix  thoroughly  and  heat  carefully  until  the  mass  appears  liquid 
and  in  a  quiet  state  of  fusion.  Cool  and  treat  with  hot  water  until 
the  fused  mass  is  decomposed.  If  the  solution  is  red  or  green  it 
indicates  the  presence  of  manganese;  add  a  few  drops  of  alcohol, 
which  will  precipitate  the  manganese  as  manganese  dioxide.  Filter 
r.nd  wash  with  hot  water.  Acidulate  the  filtrate  with  hydrochloric 


32  METALLURGICAL  ANALYSIS 

acid  and  evaporate  to  complete  dryness.  Treat  the  residue  with 
water  and  a  few  drops  of  hydrochloric  acid,  heat  and  filter.  Wash 
with  hot  water;  heat  the  filtrate  to  boiling  and  precipitate  the  sul- 
phur with  a  hot  solution  of  barium  chloride.  Allow  the  precipitate 
to  settle,  filter,  wash  with  hot  water,  ignite  and  weigh  as  barium 
sulphate.  Calculate  the  per  cent,  of  sulphur  in  the  ore. 

Aqua  Regia  Method — Weigh  out  from  one  to  five  grams  of  the 
finely  pulverized  ore.  If  high  in  sulphur,  one  gram ;  if  low  in 
sulphur,  five  grams.  Place  in  a  beaker  and  add  about  20  c.c.  of 
aqua  regia  for  every  gram  of  ore  taken.  Cover  the  beaker  and 
warm  for  some  time,  then  remove  cover  and  evaporate  to  dryness. 
Allow  to  cool.  Moisten  the  residue  with  hydrochloric  acid ;  add 
water,  heat,  and  filter.  Dilute  the  filtrate  to  about  200  c.c. ;  heat 
to  boiling;  add  solution  of  barium  chloride  to  precipitate  the  sul- 
phur as  barium  sulphate.  Allow  the  precipitate  to  settle,  filter, 
wash  with  hot  water,  ignite  and  weigh.  Calculate  per  cent,  of 
sulphur  in  the  ore. 


DETERMINATION  OF  SILICA  IN  IRON  ORES. 

Method  I — Dissolve  one  gram  of  the  pulverized  ore  in  hydro- 
chloric acid ;  evaporate  to  dryness.  Moisten  the  residue  with  con- 
centrated hydrochloric  acid ;  add  water,  heat,  filter,  wash  and  ig- 
nite and  weigh  the  insoluble  residue  in  a  platinum  crucible.  Treat 
the  residue  with  hydrofluoric  acid  and  a  few  drops  of  sulphuric 
acid;  evaporate  to  dryness*;  ignite  and  weigh.  In  almost  all  iron 
ores  the  loss  in  weight  would  represent  the  silica.  If,  however, 
the  insoluble  residue  contains  calcium,  magnesium,  sodium,  or 
potassium,  the  loss  in  weight  would  not  represent  the  silica,  but 
should  be  increased  by  the  amount  of  So^  found  in  the  insoluble 
residue  in  combination  with  these  elements. 

To  determine  the  SO0,  fuse  the  residue  with  a  little  carbonate 
of  soda,  dissolve  in  hot  water,  acidulate  with  hydrochloric  acid, 
heat  to  boiling,  and  add  a  solution  of  barium  chloride.  Filter  off 
the  precipitate,  ignite  and  weigh  as  barium  sulphate.  Calculate 
the  amount  of  SOg  and  add  its  weight  to  the  loss  by  volatilization 
vith  the  hydrofluoric  acid. 

Method  II — Weigh  one  gram  of  the  ore  into  a  platinum  cruci- 


METALLURGICAL  ANALYSIS  33 

ble,  and  mix  with  about  eight  times  its  weight  of  carbonate  of 
soda;  fuse  thoroughly;  dissolve  the  fused  mass  in  hot  water; 
acidulate  with  hydrochloric  acid ;  evaporate  to  dryness  in  a  casser- 
ole;  heat  the  residue  for  a  short  time  at  a  temperature  of  110°  to 
130°  C.  Moisten  the  residue  with  concentrated  hydrochloric 
acid ;  add  water,  heat  and  filter.  Wash  alternately  with  dilute  hy- 
drochloric acid  and  water,  ignite  and  weigh  the  silica. 

If  greater  accuracy  is  desired  the  -silica  may  be  treated  with 
hydrofluoric  acid  and  sulphuric  acid ;  the  loss  after  evaporation 
and  ignition  is  weight  of  silica. 

The  nitrate  from  the  silica  may  be  used  for  the  determination 
of  alumina. 

Method  If! — Treat  about  one  gram  of  the  ore  in  a  number  two 
beaker  with  20  c.c.  of  concentrated  hydrochloric  acid.  Cover  the 
beaker  and  heat  until  the  ore  is  decomposed.  Remove  the  cover 
and  evaporate  to  dryness.  Moisten  the  residue  with  concentrated 
hydrochloric  acid,  add  water,  heat  and  filter.  Wash  with  water, 
ignite  the  residue  in  a  platinum  crucible,  and  fuse  with  eight  parts 
of  sodium  carbonate.  Cool ;  treat  the  fused  mass  with  dilute 
hydrochloric  acid,  evaporate  to  dryness ;  heat  for  some  time  at  a 
temperature  of  from  110°  to  130° C.  Moisten  the  residue  with 
concentrated  hydrochloric  acid,  add  water,  heat  and  filter.  Wash 
with  hot  water,  ignite  and  weigh  the  silica. 

The  combined  filtrates  from  the  silica  may  be  used  for  the  de- 
termination of  alumina. 

Reference:  W.  F.  Hellebr,and,  Jour.  Am.  Chem.  Soc.,  Vol.  XXIV, 
page  435. 

DETERMINATION  OF  ALUMINA  IN  IRON  ORES. 

About  i.  gram  of  the  finely  pulverized  ore  is  dissolved  in  15  c.c. 
of  concentrated  hydrochloric  acid,  the  siliceous  residue  filtered  off 
and  ignited  in  a  platinum  crucible  and  the  silica  volatilized  as  sili- 
con tetrafluoride,  SiFl4 ;  with  hydrofluoric  acid.  The  residue  from 
the  silica  is  then  fused  with  anhydrous  sodium  carbonate,  and  the 
fusion  decomposed  with  water  and  hydrochloric  acid,  and  added 
to  the  original  filtrate.  A  solution  of  hydrogen  sodium  phosphate, 
somewhat  in  excess  of  the  required  amount  to  precipitate  the  alu- 
minum is  then  added  (about  20  c.c.  of  a  10%  solution). 


34  METALLURGICAL  ANALYSIS 

The  solution  is  neutralized  with  ammonia  water  using  a  drop 
or  two  of  methyl  orange  for  the  indicator  and  then  just  sufficient 
hydrochloric  acid  is  added  to  dissolve  the  precipitated  phosphate. 
It  should  require  about  3.5  c.c.  of  the  concentrated  hydro.chloric 
acid.  A  solution  of  sodium  thiosulphate  sufficient  to  neutralize 
the  acid  is  then  added.  This  will  require  about  15  grams  of  the 
thiosulphate  which  should  be  dissolved  in  about  75  c.c.  of  dis- 
tilled water  before  being  added.  Sulphur  is  precipitated  and  the 
iron  reduced  to  the  ferrous  state.  The  solution  is  next  diluted 
with  water  to  400  or  500  c.c.,  heated  to  boiling,  15  c.c.  of  acetic 
acid  (sp.  gr.  1.04)  added,  and  boiled  for  about  one-half  hour,  or 
until  SO  is  expelled.  The  precipitate  is  filtered,  washed,  ignited 
in  a  porcelain  crucible  and  weighed  as  AlPo^.  Calculate  per  cent. 


DETERMINATION  OF  TITANIUM  IN  IRON  ORES. 

One  gram  of  the  finely  pulverized  ore  intimately  mixed  in  a 
large  platinum  crucible  with  12  grams  of  potassium  di-sulphate 
and  2  grams  of  sodium  fluoride  is  gradually  heated  by  a  low 
flame  until  the  di-sulphate  is  melted.  Heating  is  continued,  keep- 
ing the  mass  just  liquid  and  the  temperature  at  the  point  at 
which-  slight  fumes  of  sulphuric  anhydride  are  given  off  when  the 
lid  of  the  crucible  is  raised,  until  all  the  particles  of  the  ore 
have  disappeared.  Remove  the  flame,  and,  as  the  melt  cools, 
incline  the  crucible  in  different  directions,  so  that  the  fused 
mass  may  solidify  well  up  on  the  sides.  When  cool  add  2  or  3 
c.c.  concentrated  sulphuric  acid,  and  carefully  heat  until  the 
mass  is  just  liquid.  Discontinue  heating,  and  place  a  platinum 
rod  in  the  solidifying  melt.  When  cold,  fuse  the  mass  where 
it  is  in  contact  with  the  crucible,  and  remove  it  by  means  of 
the  platinum  rod  to  a  beaker  containing  150-200  c.c.  of  a  5 
per  cent,  solution  of  sulphuric  acid.  In  the  beaker  also  place 
the  crucible  and  cover.  Gently  warm,  but  do  not  raise  the  temper- 
ature of  the  beaker  and  its  contents  beyond  that  which  can  be  com- 
fortably endured  by  the  palm  of  the  hand.  The  melt  should  com- 
pletely dissolve  to  a  clear  solution.  Determine  the  titanium  in 
the  solution  by  one  of  the  following  methods. 


METALLURGICAL  ANALYSIS  35 

Gooch's  Method — Add  50  c.c.  of  sulphurous  acid  and  gently 
warm  for  a  few  minutes.  The  solution  is  cooled  and  neutralized 
with  ammonia  until  the  precipitate  which  forms  dissolves  with 
difficulty.  Add  10  c.c.  of  sulphurous  acid,  20  grams  of  sodium 
acetate  (in  solution),  and  one-sixth  the  total  volume  of  acetic 
acid  (sp.  gr.  1.04).  The  solution  is  heated  to  boiling,  the 
titanium  being  precipitated  in  a  flocculent  condition.  Boiling 
is  continued  for  two  or  three  minutes.  If  filtered  immediately, 
the  filtrate,  upon  evaporation,  is  sometimes  found  to  contain 
traces  of  titanic  acid ;  this,  however,  may  be  obviated  by  digest- 
ing the  previously  boiled  precipitate  on  the  steam  bath  for  half 
an  hour. 

After  allowing  the  precipitated  titanic  acid  to  settle,  filter, 
wash  with  hot  water  containing  5  per  cent,  of  acetic  acid,  and 
finally  with  hot  water.  The  titanic  acid  precipitate  is  generally 
contaminated  more  or  less  with  iron,  alkali  sulphates,  alumina, 
phosphoric  acid,  etc.  In  order  to  eliminate  these  impurities,  the 
precipitate  is  thoroughly  ignited  in  a  platinum  crucible  to  burn 
out  the  carbon  of  the  filter  paper,  and  then  fused  with  sodium 
carbonate  (avoid  presence  of  potassium  carbonate)  and  a  little 
sodium  nitrate,  in  order  to  form  soluble  phosphate  and  alu- 
minate  of  sodium ;  the  titanium,  at  the  same  time  is  converted 
into  insoluble  sodium  titanate,  and  the  iron  into  insoluble  ferric 
oxide.  A  liberal  amount  of  the  flux  and  an  hour's  fusion  with  the 
strong  flame  of  a  blast  lamp  are  necessary  to  effect  these 
changes  completely.  After  fusion,  the  melt  is  boiled  with  a 
solution  of  sodium  carbonate,  filtered  and  washed  with  water 
containing  a  little  sodium  carbonate.  The  insoluble  sodium 
titanate  and  ferric  oxide  are  collected  on  a  filter,  dried  in  an 
air-bath,  and  transferred  to  a  platinum  crucible.  The  filter 
paper  is  burned  on  a  platinum  wire,  and  the  residue  also  added 
to  the  crucible.  The  contents  of  the  crucible  are  fused  with  a 
little  sodium  carbonate,  and  the  cooled  mass  treated  in  the 
crucible  with  sulphuric  acid,  heat  being  gradually  applied  until 
fumes  of  sulphuric  anhydride  are  evolved.  After  cooling,  the 
liquid  or  pasty  mass  is  dissolved  in  a  mixture  of  ico  c.c. 
water  and  20  c.c.  sulphurous  acid.  Then,  after  neutralizing  with 
ammonia  until  the  precipitated  titanic  acid  dissolves  with  diffi- 
culty, 5  to  10  grams  of  sodium  acetate  (in  solution)  and  25 


36  METALLURGICAL  ANALYSIS 

c.c.  of  acetic  acid  (sp.  gr.  1.04)  are  added.  The  solution  is 
boiled  for  several  minutes ;  digested  on  the  steam  bath  for  half 
an  hour  at  a  temperature  just  below  boiling;  the  precipitated 
titanic  hydrate  filtered ;  washed  with  hot  water  containing  5 
per  cent,  of  acetic  acid,  and  finally  with  hot  water;  ignited  and 
weighed  as  titanic  oxide  (TiOi). 

Bettel's  Method — To  the  solution  add  sodium  carbonate  so 
long  as  it  can  be  added  without  forming  a  permanent  precipitate. 
Then  add  3  c.c.  of  dilute  sulphuric  acid  and  100  or  150  c.c.  of  a 
strong  solution  of  sulphurous  acid ;  dilute  with  cold  water  to- 
about  700  c.c.  Cover  with  a  watch  glass  and  slowly  heat  to 
boiling.  Continue  the  boiling  for  about  two  hours.  Add  hot 
water  and  a  little  sulphurous  acid  from  time  to  time  during  the 
boiling  so  as  to  keep  the  bulk  of  the  solution  to  about  700  c.c. 
During  the  boiling,  sulphur  dioxide  should  always  be  present  to- 
keep  the  iron  reduced  to  the  ferrous  form,  otherwise  more  or  less 
iron  would  be  precipitated  along  with  the  titanium  dioxide.  Al- 
low the  precipitate  to  settle.  (Do  not  use  filter  pump.)  Filter, 
wash  with  water  containing  a  little  sulphurous  acid  and  a  little 
ammonium  sulphate.  Dry,  ignite  in  a  platinum  crucible,  partly 
cool,  add  a  few  pieces  of  .solid  ammonium  carbonate  and  again 
ignite  to  remove  traces  of  sulphuric  anhydride.  Cool  and  weigh 
as  Ti02. 

This  may.  contain  traces  of  iron  oxide,  calcium  sulphate  or 
phosphoric  acid,  therefore  if  very  accurate  results  are  desired, 
weigh  into  the  crucible  six  or  eight  parts  of  carbonate  of  soda  and 
mix  it  with  the  TiO0  and  fuse  thoroughly.  Cool,  dissolve  the  fused 
mass  in  hot  water,  filter  and  wash  with  hot  water.  Ignite  the 
precipitate  of  titanate  of  soda  (Na0O.  TiO  )  in  a  platinum  cruci- 
ble and  fuse  it  with  about  15  times  its  weight  of  potassium  bi- 
sulphate,  observing  the  same  precautions  as  in  first  fusion.  Cool, 
place  in  a  beaker,  add  cold  water.  When  decomposed,  filter,  if 
necessary  and  wash  with  cold  water.  Determine  the  titanium  in 
the  filtrate  by  either  of  the  following  methods : 

(a)  Dilute  and  precipitate  titanium  di-oxide  by  boiling  in  pres* 
ence  of  sulphurous  acid.    Filter,  ignite  and  weigh  TiO2. 

(b)  To  the  solution  add  about  50  c.c.   sulphurous  acid,  and 
about  10  grams  of  sodium  acetate  and  40  c.c.  strong  acetic  acid, 
heat  to  boiling  for  about  15   minutes.     Allow  the  precipitate  to 


METALLURGICAL  ANALYSIS  37 

settle,  filter,  wash  with  hot  water  containing  a  little  acetic  acid, 
dry,  ignite  and  weigh  TiO0. 

Welter's  Color  Method. 

Dilute  the  solution  to  500  c.c.  with  5  per  cent,  sulphuric  acid 
and  mix  thoroughly.  Put  50  c.c.  of  the  solution  into  a  compar- 
ison tube.  Put  into  a  second  comparison  tube  as  much  of  a  stan- 
dard ferric  sulphate  solution,  containing  5  per  cent  sulphuric  acid, 
as  will  contain  an  amount  of  iron  equal  to  that  in  o.i  gram  of 
the  ore  and  dilute  to  50  c.c.  with  5  per  cent,  sulphuric  acid. 

Add  to  each  tube  5  c.c.  of  hydrogen  peroxide  and  then  add 
to  the  second  tube  from  a  burette  a  standard  solution  of  titanium 
sulphate  until  the  yellow  color  produced  matches  that  in  the  first 
tube.  From  the  volume  of  the  standard  solution  used  calculate 
the  percent  of  TiO0  in  the  ore. 

To  prepare  the  standard  titanium  sulphate  solution  fuse  0.5 
gram  of  pure  TiO0  in  a  platinum  crucible  with  5  grams  of  potas- 
sium bisulphate.  Cool  and  dissolve  the  fusion  in  5  per  cent,  sul- 
phuric acid.  Dilute  the  solution  to  500  c.c.  with  the  5  per  cent, 
acid. 

This  method  is  very  satisfactory  for  the  determination  of  titan- 
ium in  ores  containing  less  than  about  4  per  cent.  For  ores  con- 
taining more  than  4  per  cent  the  Gooch  method  is  recommended. 

References  : 

Gooch,  Proc.  Am.  Acad.  Arts  and  Sciences,  New  Series,  Vol.  XIIr 
page  435. 

A.   A.   Blair,   The  Chemical  Analysis  of  Iron. 

F.  J.  Pope,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  XXIX,  page  372. 

J.  O.  Arnold,  .Steel  Works  Analysis. 

H.  L.  Wells  and  W.  L.  Mitchell,  Jour.  Am.  Chem.  Soc.,  Vol. 
XVII,  page  878. 

W.  Bettel.  See  Crooke's  Select  Methods,  page  194. 

J.  W.  Bain,  Jour.  Am.  Chem.  8oc.,  Vol.  XXV,  page  1073. 

Weller,  Bcr.  <l.   Chem.  Oes.,  Vol.  XV,  page  2593. 


DETERMINATION  OF  MOISTURE  IN  IRON  ORES. 

Weigh  out  one  or  two  grams  of  ore  in  a  bulb  tube  and  ignite 
in  a  slow  current  of  dry  air.  Collect  the  water  in  a  weighed 
calcium  chloride  tube  which  is  connected  with  the  bulb  ignition 
tube.  The  increase  in  weight  of  the  calcium  chloride  tube  gives 
the  amount  of  moisture  in  the  sample.  Calculate  the  per  cent. 


38  METALLURGICAL  ANALYSIS 

DETERMINATION  OF  CARBONIC  ACID  IN  IRON  ORES. 

Take  for  this  determination  from  one  to  five  grams  of  the 
pulverized  ore,  the  amount  taken  depending  upon  the  amount 
of  carbonic  acid  expected.  Decompose  the  carbonate  in  a  flask 
which  is  connected  with  a  weighed  caustic  potash  absorption 
bulb.  The  increase  in  weight  of  the  absorption  bulb  gives  the 
weight  of  carbon  dioxide  in  the  sample. 

DETERMINATION  OF  FERROUS  IRON  IN  IRON  QRES. 

Weigh  into  a  large  platinum  crucible  one  gram  of  the  finely 
pulverized  ore  and  heat  on  a  water  bath  with  about  20  c.c. 
concentrated  hydrochloric  acid  and  about  20  c.c.  of  hydro- 
fluoric acid.  A  water  bath  constructed  for  this  process  is  pro- 
vided with  a  grooved  ring  in  which  a  funnel  stands.  A 
little  water  placed  in  the  groove  forms  a  tight  joint.  It  is 
.also  provided  with  a  tube  in  the  side  through  which  carbon 
dioxide  can  be  passed  to  exclude  the  air  during  the  process,  and 
thus  prevent  any  oxidation  of  the  ferrous  iron.  Stir  the  con- 
tents of  the  crucible  from  time  to  time*  with  a  long  platinum  wire. 
When  the  ore  is  dissolved  transfer  the  contents  of  the  crucible 
to  a  beaker.  Add  water  and  determine  the  ferrous  iron  present 
by  means  of  a  standard  solution  of  potassium  bichromate. 
Calculate  the  per  cent,  of  FeO. 

COMPLETE  ANALYSIS  OF  IRON  ORES. 

(Method  suitable  for  all  iron  ores  excepting  those  containing 
•considerable  titanic  acid.) 

Treat  five  grams  of  the  finely  ground  ore  in  a  number  three 
beaker  with  about  50  c.c.  strong  hydrochloric  acid  and  one 
or  two  c.c.  strong  nitric  acid.  Heat  the  mixture  until  the 
ore  is  decomposed.  Evaporate  to  dryness  in  order  to  render 
insoluble  any  silica  which  may  have  been  dissolved.  Moisten 
the  residue  with  concentrated  hydrochloric  acid,  add  water, 
heat,  filter  into  a  250  c.c.  flask.  Wash  with  water,  ignite  the 
siliceous  residue  in  a  platinum  crucible  and  fuse  it  with  about 
eight  times  its  weight  of  carbonate  of  soda.  Decompose  the  fused 
mass  with  water,  acidify  with  hydrochloric  acid,  evaporate  to 


METALLURGICAL  ANALYSIS  39. 

dryness;  heat  in  a  drying  oven  for  an  hour  at  110°  to  I2O°C 
Cool,  moisten  with  concentrated  hydrochloric  acid,  add  water, 
heat,  filter  into  the  250  c.c.  flask  containing  the  first  filtrate.  Wash 
with  hot  water,  ignite  and  weigh  the  SiO0.  Dilute  the  solution 
in  the  flask  to  the  containing  mark  and  mix  thoroughly. 

Determination  of  the  Iron — Take  out  50  c.c.  of  the  solution. 
Reduce  the  iron  with  stannous  chloride  and  continue  as  directed 
on  page  21.  Calculate  the  per  cent,  of  Fe2Os. 

Determination  of  the  Phosphorus — To  100  c.c.  of  the  solu- 
tion add  ammonia  until  the  mass  sets  to  a  stiff  jelly,  making  sure 
that  there  is  present  an  excess  of  ammonia.  Next  add  strong 
nitric  acid  in  sufficient  amount  to  bring  the  solution  to  a  clear 
amber  color,  and  continue  as  directed  on  page  24, 

Determination  of  Alumina,  Manganese,  Lime  and  Magnesia 
• — Take  50  c.c.  of  the  solution  in  a  large  beaker,  add  sodium 
carbonate  until  the  fluid  is  nearly  neutral  and  then  to  the  clear 
red  liquid  add  a  solution  of  about  5  grams  of  sodium  or  am- 
monium acetate ;  dilute  to  about  500  c.c.  with  boiling  distilled 
water.  Heat  to  boiling  for  a  minute  or  two,  filter  while  hot 
and  wash  by  decantation  with  hot  water.  Dissolve  the  precipitate 
in  hot  dilute  hydrochloric  acid',  heat  to  boiling  then  add  ammonia 
water  to  alkaline  reaction.  Filter  and  wash  the  precipitate  with 
hot  water.  Ignite  and  weigh  Fe0O8,  A12O...  P.,O_.  Calculate 
the  per  cent,  of  Fe,O3,  A10O,  and  P0O.'.  The  per"  cent,  of  A10O3 
is  determined"  by  subtracting  the  per  cent.  Fe,O3  and  P2O& 
previously  determined  from  the  above.  Add  the  filtrate  and  wash- 
ings from  the  acetate  precipitation  to  those  from  the  precipita- 
tion by  ammonia.  Evaporate  the  solution  to  about  75  c.c.  When 
cold  add  bromine  water  until  the  solution  is  strongly  colored, 
add  ammonia  in  excess  and  heat  moderately  for  some  time,  then 
filter,  wash  with  hot  water.  Test  filtrate  for  manganese  with 
more  bromine  and  ammonia,  heat  for  some  time  and  filter  if 
necessary,  dry,  ignite  and  weigh  Mn.?O4.  Calculate  the  percent. 
MnO0. 

Instead  of  igniting  the  precipitate  of  hydrated  peroxide  of 
manganese,  it  may  be  dissolved  in  an  excess  of  standard  ferrous 
sulphate  solution,  containing  a  little  sulphuric  acid,  and  the 
excess  of  the  ferrous  salt  determined  with  a  standard  solution 
of  permanganate  or  bichromate  of  potash.  See  Ford- Williams 
process,  page  30. 


40 


METALLURGICAL  ANALYSIS 


Acidify  the  filtrate,  from  the  manganese  precipitate,  with  hy- 
drochloric acid  and  concentrate  to  about  100  c.  c.  Add  am- 
monia in  slight  excess,  then  precipitate  the  calcium  with  am- 
monium oxalate  as  calcium  oxalate,  CaC2(X  Filter,  wash,  ignite 
and  weigh  CaO.  Calculate  the  per  cent,  of  CaO. 

To  the  filtrate  from  the  calcium  oxalate  add  a  volume  of 
ammonia  of  sp.  gr.  96,  equal  to  one  third  the  volume  of  the 
solution.  Then  add  hydrogen  sodium  phosphate  drop  by  drop 
while  stirring  the  solution  with  a  glass  rod,  to  precipitate  the 
magnesium  as  ammonium  magnesium  phosphate.  Allow  to 
stand  for  some  time,  filter,  wash  with  a  mixture  of  one  part 
of  ammonia,  sp.  gr.  .96,  and  three  parts  water,  dry,  ignite  and 
weigh  Mg9P2O7.  Calculate  the  per  cent,  of  MgO. 

Determination  of  the  Sulphur — To  the  remaining  50  c.c.  of  the 
original  solution  add  a  few  drops  of  hydrochloric  acid,  heat  to 
boiling  in  a  beaker  and  precipitate  the  sulphur  with  barium 
chloride  as  barium  sulphate,  BaSCX.  Allow  the  precipitate  to 
settle,  filter,  wash,  ignite  and  weigh  BaSCX  Calculate  the  per 
cent,  of  sulphur. 

Determination  of  Carbon  Dioxide,  Moisture  and  Ferrous  Iron. 
See  page  37. 


DETERMINATION  OF  TOTAL  CARBON  IN  IRON  AND 

STEEL. 

BY  OXIDATION   OF  THE   CARBON    WITH   CHROMIC   ACID  AND   SULPHURIC 
ACID    AFTER   THE   REMOVAL   OF   THE   IRON. 

Treat  about  one  gram  of  the  pig  iron  or  cast  iron  drillings 
in  a  number  two  beaker  with  a  hundred  c.c.  of  saturated  solu- 
tion (300  grams  per  liter)  of  copper  potassium  chloride  and 
7.5  c.c.  of  .strong  hydrochloric  acid.  For  steel,  treat  about  3  grams 
in  a  number  three  beaker  with  200  c.c.  of  the  copper  potassium 
chloride  and  15  c.c.  of  strong  hydrochloric  acid.  Stir  the  solu- 
tion vigorously  for  a  few  minutes,  place  the  beaker  in  a  warm 
place,  but  not  where  the  temperature  can  rise  above  60°  or  70° C. 


/ 
c 


METALLURGICAL  ANALYSIS 


Continue  to  stir  at  frequent  intervals  until  the  precipitated  cop- 
per is  dissolve^.     Reactions  are: 

Fe+CuCl2=FeCl2+Cu 

Cu+CuCl0=2CuCl. 

Allow  the  undissolved  residue  to  subside  and  then  filter 
through  an  ignited  asbestos  filter.  The  filter  may  be  made  by 
placing  a  small  perforated  platinum  or  porcelain  disc  in  the 
bottom  of  a  small  funnel,  and  upon  it  is  placed  in  the  usual 
manner  the  asbestos  which  has  been  previously  ignited.  Wash 
the  residue  at  first  with  a  little  dilute  hydrochloric  acid  and 
then  with  hot  water. 

OXIDATION    OF    THE    CARBONACEOUS    RESIDUE. 

Apparatus  required: 

i.     A  flask,  A,  (see  Fig.  i),  having  a  capacity  of  about  300  c.c. 

DEC 


provided  with  a  double  perforated  rubber  stopper.  Through 
one  of  the  holes  is  passed  a  separating  funnel,  B,  with  glass 
stopcock.  The  funnel  should  have  a  capacity  of  about  100  c.c. 
Through  the  other  hole  of  the  stopper  is  passed  a  condenser,  C, 
through  which  a  stream  of  water  continually  passes  while  the 
combustion  is  being  made. 

II.  An  apparatus,  D,  for  the  purification  of  the  air.  This 
consists  of  a  U  tube  filled  partly  with  pieces  of  solid  potassium 
hydroxide  and  partly  with  granular  calcium  chloride. 


42  METALLURGICAL  ANALYSIS 

III.  A    series    of    connected    U    tubes    in    which    the   carbon 
dioxide   is   dried   and   purified   before    entering   the   weighed    ab- 
sorption apparatus. 

E  contains  a  solution  of  silver  sulphate  and  concentrated  sul- 
phuric acid. 

F,  a   U   tube   filled   with    pumice  .stone   which   has   been    sat- 
urated   with    a    concentrated    solution    of    copper    sulphate,    and 
then  heated  to  dehydrate  the  salt. 

G,  a  U  tube  filled  with  granular  calcium  chloride. 

IV.  An  apparatus,  H,  for  the  absorption  of  carbon  dioxide, 
containing  a  solution  of  potassium  hydroxide,  sp.  gr.    1.27    (two 
parts  KOH  to  three  parts  H0O).     This  absorption  apparatus  is 
connected    with    a    tube,    I,    partly    filled    with    granular    calcium 
chloride  and  partly  with  soda  lime.     This  tube  is  to  protect   H 
from  carbon  dioxide  and  moisture  of  the  air. 

Process — Transfer  the  asbestos  filter  and  carbonaceous  res- 
idue to  the  combustion  flask  A.  If  necessary  clean  the  funnel 
with  a  little  ignited  asbestos  and  place  it  in  the  flask  with  the 
residue.  Weigh  the  apparatus  for  the  absorption  of  the  car- 
bonic acid  gas  and  connect  it  properly  with  the  tubes  G  and  I. 
Add  through  the  separating  funnel  10  c.c.  of -a  saturated  solution 
of  chromic  acid,  and  then  slowly  add  100  c.c.  of  concentrated 
sulphuric  acid,  which  has  been  heated  nearly  to  the  boiling 
point  with  a  little  chromic  acid,  and  then  cooled.  Pass  a  slow 
current  of  air  through  the  whole  apparatus  and  very  gradually 
raise  the  temperature  of  the  liquid  in  the  flask  nearly  to  the 
boiling  point.  The  reaction  is : 

3C+4Cr03+6H2S04=r2Cr2  ( SO4)  3+3CO2+6H2O. 

When  the  oxidation  is  complete,  gradually  lower  the  light 
while  a  current  of  air  continues  to  pass.  Extinguish  the  light 
and  when  about  one  liter  of  air  has  passed  through  the  appar- 
atus after  the  extinguishing  of  the  flame,  detach  and  weigh  the 
carbon  dioxide  absorption  apparatus.  The  increase  in  weight 
is  CO,.  Calculate  per  cent,  carbon.  Results  should  agree  within 
.01  per  cent. 


METALLURGICAL  ANALYSIS 


43 


DETERMINATION  OF  TOTAL  CARBON  IN  IRON  AND 

STEEL. 

BY    COMBUSTION    OF    THE    CARBON    IN    THE    SHIMER    CRUCIBLE    AFTER 
THE    REMOVAL    OF    THE    IRON. 

Separate  the  iron  from  the  carbon  as  directed  in  the  pre- 
ceding experiment.  Dry  the  carbonaceous  residue  in  an  air  bath 
for  about  half  an  hour  at  ioo°C.  When  dry,  transfer  it  to 
the  Shimer  crucible  with  the  carbon  side  down.  It  is  well 
to  have  a  circular  piece  of  thin  platinum  foil  in  the  bottom  of 
the  crucible.  The  carbon  should  all  be  kept  within  one-fourth 
of  an  inch  of  the  bottom  of  the  crucible,  otherwise  a  part  of 
the  carbon  might  escape  combustion. 

Partly  fill  the  crucible  with  ignited  asbestos. 

The  Shimer  crucible  is  a  special  water- jacketed  platinum  cru- 
cible closed  by  a  hollow  water-cooled  metal  stopper  made  gas- 
tight  by  means  of  a  rubber  band.  See  Fig.  2.  Place  the  rubber 
band  around  the  crucible  stopper  and  insert  it  in  the  crucible. 


H 

\h 

"a 

— 

T 

1 

\? 

. 
I 

Fig.  2 

The  crucible  is  supported  by  passing  it  about  half-way  through 
a  heavy  piece  of  asbestos  board.  The  crucible  is  connected, 
by  means  of  the  water  inlet  tube,  with  a  water  supply  for  cooling 
the  stopper.  Under  the  crucible  is  an  upright  Bunsen  burner 
or  blast  lamp.  If  the  carbonaceous  matter  is  mainly  graphite  it 
will  require  the  strong  heat  of  a  blast  lamp  to  make  the  com- 
bustion. 

Connected  with  the  air  inlet  tube  is  Geissler's  bulb  containing 


44  METALLURGICAL  ANALYSIS 

solution  of  potassium  hydroxide  (sp.  gr.  1.27)  for  purification 
of  the  air.  Between  the  Geissler  bulb  and  the  crucible  is  a  small 
guard  bottle  to  retain  any  drops  of  the  potassium  hydroxide  that 
may  be  forced  over  from  the  Geissler  apparatus. 

An  aspirator  to  furnish  air  pressure  is  connected  with 
the  Geissler  bulb.  Next  to  the  crucible  and  connected  to  it  by 
means  of  the  air  outlet  tube  is  a  short  brass  tube  containing 
cupric  oxide  in  its  central  portion  and  provided  with  wet  wick 
at  the  ends  for  cooling  purposes.  Next  to  the  cupric  oxide  tube 
is  a  glass  tube  filled  with  glass  beads,  wet  with  distilled  water,  for 
retaining  hydrochloric  acid  and  chlorine. 

Next  to  the  glass  bead  tube  is  attached  a  large  calcium 
chloride  tube. 

The  calcium  chloride  tube  is  connected  with  a  weighed  Geiss- 
ler bulb  containing  potassium  hydroxide  (sp.  gr.  1.27)  and  the 
Geissler  bulb  with  a  guard  tube  of  calcium  chloride. 

Be  sure  that  the  water  is  running  from  the  stopper  and  that 
the  cupric  oxide  tube  is  red  hot  for  from  one  and  one-half  to 
two  inches  in  its  central  part,  then  turn  on  the  air  at  the  speed 
of  about  three  bubbles  per  second  and  bring  a  small  blast- 
lamp  flame  immediately  under  the  crucible,  so  as  to  heat  the 
bottom  to  a  bright  red  heat,  extending  at  least  one-fourth  inch 
from  the  bottom.  A  large  flame  should  be  avoided.  Time  re- 
quired for  making  combustion  about  twenty-five  minutes. 

References : 

P  W  Shimer,  Jour.  Am.  Chem.  Soc.,  Vol.  XXI,  page  557 ;  and 
Vol.  XXIII,  page  227  ;  and  Vol.  XXV,  page  997. 

G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.  XXIV,  page  1206. 

J.  V.  R.  Stehman,  Jour.  Am.  Chem.  Soc.,  Vol.  XXV,  page  237. 

DETERMINATION  OF  GRAPHITIC  CARBON  IN  IRON. 

METHOD    I. 

Dissolve  one  gram  of  pig  iron  in  15  c.c.  of  nitric  acid  of  sp. 
gr.  1.2.  Collect  the  undissolved  material  upon  an  ignited  as- 
bestos filter  and  wash  with  hot  water.  Treat  the  residue  on  the 
filter  with  a  hot  solution  of  potassium  hydrate  of  i.i  specific 
gravity.  Wash  thoroughly  with  hot  water,  then  with  a  little 
dilute  hydrochloric  acid  and  finally  with  hot  water.  Burn  the 
carbon  with  chromic  and  sulphuric  acids.  See  page  41. 


METALLURGICAL  ANALYSIS  45 

A  very  satisfactory  result  may  be  obtained  as  follows :  Place 
the  asbestos  filter  and  graphite  in  a  platinum  crucible.  Dry  the 
crucible  and  contents  at  ioo°C,  cool  and  weigh.  Heat  over  a 
Bunsen  burner  until  the  graphite  is  all  burned  off  and  weigh 
again.  The  loss  of  weight  gives  graphite. 

METHOD    II. 

Dissolve  2  grams  of  pig  iron  in  50  c.c.  of  dilute  nitric  acid 
(sp.  gr.  1.2)  in  a  number  four  beaker,  heat  gently  to  boiling 
and  then  boil  for  about  five  minutes  Next  add  about  5  c.c. 
hydrofluoric  acid,  being  careful  not  to  allow  it  to  touch  the 
glass.  Immediately  give  the  beaker  an  oscillatory  motion,  heat 
a  few  moments,  dilute  with  water  and  filter  onto  a  filter  paper 
which  has  been  dried  at  ioo°C.  and  then  weighed.  Wash  at 
first  with  hot  water  and  then  two  or  three  times  with  dilute 
hydrochloric  acid.  Wash  again  with  water  and  then  twice  with 
ammonia  and  finally  several  times  with  water.  Dry  the  filter 
paper  and  graphite  at  ioo°C.  and  weigh.  Calculate  per  cent 
graphite.  If  extreme  accuracy  is  required,  place  the  dried  and 
weighed  paper  and  graphite  in  a  platinum  crucible  and  thoroughly 
burn  off  paper  and  graphite  and  weigh  the  siliceous  residue.  This 
weight  of  silica  should  be  multiplied  by  1.06  and  the  product 
deducted  from  the  weight  of  graphite  as  found  above. 

References : 

P.  W.  Shimer,  Jour.  Am.  Chcm.  Soc.  Vol.  XVII,  page  873. 
G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.  XXII,  page  47. 

F.  L.   Crobough,  Jour.  Am.  Chem.  Soc.,  Vol.  XVI,  page  104. 

G.  T.  Dougherty,  Chem.  News,  Sept.  8,  1899. 

T.  M.  Drown,  Trans.  Am.  Inst.  Min.  Engrs.,  Vol.  II,  page  224. 


DETERMINATION  OF  COMBINED  CARBON. 

EGGERTZ    COLORIMETRIC    METHOD. 

The  method  depends  upon  the  fact  that  when  samples  of 
similar  varieties  of  steel  or  iron  are  dissolved  in  nitric  acid 
(sp.  gr.  1.2)  the  depth  of  the  brown  color  produced  is  directly 
proportional  to  the  amount  of  chemically  combined  carbon  in 
the  samples.  •  The  combined  carbon  in  a  sample  of  steel  may  be 


46  METALLURGICAL  ANALYSIS 

determined  by  comparing  the  color  produced  upon  dissolving  a 
known  weight  of  the  sample  in  nitric  acid  with  the  color  produced 
by  dissolving  a  weighed  quantity  of  similar  steel  whose  per- 
centage of  combined  carbon  has  been  very  accurately  determined 
by  the  combustion  method.  See  page  40. 

Process — Clean,  dry  and  number  several  test  tubes.  Weigh 
into  one  .2  gram  of  standard  steel  and  into  the  other  the  same 
amount  of  each  sample  to  be  tested.  Add  to  each  tube  the  re- 
quired amount  of  nitric  acid  of  sp.  gr.  1.2. 

For  steels  containing  less  than  .3%  combined  carbon  use  3 
c.c.  HNO.,  sp.  gr.  1.2. 

For  steels  containing  -3-.5%  combined  carbon  use  4  c.c.  HNO3 
sp.  gr.  1.2. 

For  steels  containing  .5-.8%  combined  carbon  use  5  c.c.  HNO3 
sp.  gr.  1.2. 

For  steels  containing  .8-1%  combined  carbon  use  6  c.c.  HNO3 
sp.  gr.  1.2. 

For  steels  containing  i%  and  over  combined  carbon  use  7  c.c. 
HNO3  sp.  gr  1.2. 

Place  a  small  funnel  in  the  mouth  of  each  test  tube.  Heat 
them  in  a  water  bath,  shaking  them  from  time  to  time,  until  all 
of  the  carbonaceous  matter  is  dissolved.  Remove  each  test  tube 
and  place  it  in  a  cold  water  bath  as  soon  as  the  solution  becomes 
clear.  When  cold  pour  the  solution  of  the  standard  steel  into 
an  Eggertz  graduated  comparison  tube.  Wash  out  the  test  tube 
with  a  few  drops  of  nitric  acid  (sp.  gr.  1.2).  Dilute  the  solution 
with  water  to  about  twice  the  volume  of  the  acid  which  was  used 
in  making  it.  To  save  time  in  'making  calculation  it  is  best  to 
dilute  the  solution  to  some  convenient  multiple  of  the  carbon 
contents  of  the  steel.  Suppose  that  the  standard  steel  contains 
•35  per  cent,  combined  carbon,  dilute  the  solution  to  7  c.c. 
Then  each  c.c.  equals  .05  per  cent,  carbon.  Next  pour  the 
solution  of  a  sample  to  be  tested  into  another  Eggertz  tube, 
and  dilute  it  until  the  color  is  the  same  as  in  the  standard.  Sup- 
pose that  8  c.c.  is  the  dilution  of  the  sample,  then  it  contains 
.4  per  cent,  of  combined  carbon. 

References  : 

Trans.  Am.  Inst.  Min.  Engs.,  Vol.  I.  page  240. 
Trans.  Am.  Inst.  Min.  Engs.,  Vol.  XVI,   page  111. 
Chem.  News,  Vol.  XLVII,  page  285. 
G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.  XXV,  page  999. 


METALLURGICAL  ANALYSIS  47 

t 

DETERMINATION    OF    PHOSPHORUS   IN    IRON   AND 

STEEL. 

Treat  about  two  grams  of  the  borings  with  75  c.c.  of  nitric 
acid  (sp.  gr.  1.135),  I  part  concentrated  HNOg,  and  3  parts  water, 
in  a  400-500  c.c.  Erlenmeyer  flask  and  heat  gently.  When  the 
first  action  is  over  boil  for  one  or  two  minutes.  Add  10  c.c. 
of  potassium  permanganate  solution  (containing  12^2  grams  of 
KMnCT  per  liter),  and  boil  until  the  pink  color  disappears.  A 
precipitate  of  manganese  oxide  is  formed.  Remove  the  flask 
from  the  heat  and  add  a  little  ferrous  sulphate  (free  from  phos- 
phate) or  sugar  and  shake  the  flask  until  the  precipitate  of  man- 
ganese dioxide  dissolves.  Use  as  little  excess  of  the  ferrous 
sulphate  or  sugar  as  possible.  If  the  sample  contain  much 
graphite  it  is  best  to  filter  it  off.  To  the  solution  add  ammonia 
until  the  mass  sets  to  a  stiff  jelly.  Then  add  HNO3,  Con.  to 
get  amber  color.  Heat  the  solution  in  the  flask  to  85°C.  and 
add  about  50  c.c.  ammonium  molybdate  solution,  to  precipitate 
the  phosphorus  as  ammonio-phospho-molybdate.  Determine  the 
phosphorus  in  the  yellow  precipitate  by  the  Emmerton  method, 
page  24,  or  by  the  acidimetric  method,  page  26. 

Different  chemists  working  on  the  same  sample  should  agree 
within  .005  per  cent. 

References  : 

Dudley  &  Pease,  Jour.  Am.  Chcm.  Soc.,  Vol.  VII,  pages  108  &  519. 
Clemens  Jones,  Jour.  An.  d  Appl.  Chem.',  Vol.  IV,  page  268. 


DETERMINATION    OF    MANGANESE    IN    IRON    AND 

STEEL. 
VOLHARD'S    METHOD. 

Take  one  gram  of  the  borings.  Dissolve  the  sample  in  15 
c.c,  of  nitric  acid  (sp.  gr.  1.2)  in  a  casserole.  When  solution  is 
complete  add  10  c.c  dilute  sulphuric  acid  and  evaporate  to  dry- 
ness,  and  heat  the  residue  until  heavy  white  fumes  of  sulphuric 
acid  are  evolved  to  destroy  carbonaceous  matter.  Allow  the 
dish  to  cool,  all  100  c.c.  water,  and  heat  until  the  ferric  sulphate 


48  METALLURGICAL  ANALYSIS 

is  dissolved.  Wash  the  contents  of  the  casserole  into  a  half  liter 
flask  with  cold  water,  nearly  neutralize  with  carbonate  of  soda, 
and  proceed  from  this  point  as  directed  in  the  analysis  of  iron 
ores.  Page  28.  Different  chemists,  working  on  the  same  sample, 
should  agree  within  .01  per  cent. 

DETERMINATION     OF     MANGANESE     IN     IRON     AND     STEEL     BY     FORD- 
WILLIAMS     METHOD. 

Weigh  one  to  five  grams  of  the  iron  or  steel  and  dissolve  in 
nitric  acid  (sp.  gr.  1.2).  Use  about  15  c.c.  of  the  acid  for 
every  gram  of  iron  or  steel  taken.  In  case  of  pig  iron,  filter  off 
the  graphite  through  an  asbestos  filter.  Evaporate  to  about  10 
c.c.  Now  add  75  c.c.  of  strong  nitric  acid  and  heat.  When 
solution  is  warm  add  about  5  grams  of  potassium  chlorate  and 
boil.  From  this  point  proceed  as  in  the  analysis  of  iron  ores ; 
page  29. 

THE  COLOR    METHOD   FOR   MANGANESE  IN    IRON   AND   STEEL. 

Weigh  out  .2  gram  of  each  sample  and  the  standard.  If  the 
samples  to  be  analyzed  be  pig  iron,  then  use  a  pig  iron  standard, 
and  if  the  sample  is  steel,  a  steel  standard.  Place  the  weighed 
portions  in  10  inch  test  tubes  properly  numbered.  Pour  into  each 
20  c.c.  of  nitric  acid  (sp.  gr.  1.2).  Place  in  the  mouth  of  each 
test  tube  a  small  funnel.  Heat  in  the  water  bath  at  ioo°C.  until 
solution  is  complete,  add  10  c.c.  of  water,  heat  in  a  calcium 
chloride  bath  (which  boils  at  ii5°C.)  to  boiling,  add  about  3 
grams  of  lead  dioxide  (PbO2)  and  continue  boiling  for  just  five 
minutes.  The  reaction  is  : 
2Mn  (  NO,  )  2+s  Pb02+6H  NO8=s  Pb  (  N  O3  )  2+ 2H2O+2MnO4. 

Place  the  tubes  in  cold  water,  and  when  the  insoluble  matter 
settles,  decant  the  clear  solutions  into  the  reading  tubes  and  com- 
pare. 


DETERMINATION  OF  SULPHUR  IN  IRON  AND  STEEL. 

Method  I — Weigh  5.4936  grams  of  the  drillings  into  a  number 
3  beaker.     Add  slowly  a  mixture  of  50  c.c.   concentrated   nitric 


METALLURGICAL  ANALYSIS  49 

acid  and  one  c.c.  concentrated  hydrochloric  acid.  Heat  gently 
if  the  reaction  does  not  begin  in  the  cold,  but  remove  from  the 
heat  and  place  the  beaker  in  cold  water  if  the  reaction  is  too 
violent.  If  any  of  the  sample  resists  solution  add  a  few  drops  of 
concentrated  hydrochloric  acid  from  time  to  time.  Add  a  little 
carbonate  of  soda,  and  evaporate  to  complete  dryness. 

The  carbonate  of  soda  is  added  to  form  sodium  sulphate  and 
thus  prevent  loss  of  sulphur  trioxide,  from  the  decomposition  of 
the  iron  sulphate  in  case  the  residue  is  overheated.  Add  30  c.c. 
of  concentrated  hydrochloric  acid  and  evaporate  to  about  5  c.c. 
Add  water,  heat,  and  filter  off  the  silica.  Heat  the  filtrate  to 
boiling  and  add  10-20  c.c.  of  a  hot  solution  of  barium  chloride 
(i  to  10).  Allow  the  precipitate  to  settle,  filter,  wash  with  a 
little  dilute  hydrochloric  acid  and  then  with  hot  water,  ignite 
and  weigh  barium  sulphate.  The  weight  of  the  precipitate  in 
milligrams  divided  by  four  and  multiplied  by  ten  gives  the  per 
cent,  of  sulphur. 

Method  II — Evolution  Method — The  process  consists  in  lib- 
erating the  sulphur  from  the  iron  or  steel  by  means  of  dilute 
hydrochloric  acid,  in  the  form  of  hydrogen  sulphide  and  absorb- 
ing the  gas  in  an  ammoniacal  solution  of  cadmium  chloride,  as 
cadmium  sulphide.  The  sulphur  is  afterward  liberated  from 
the  cadmium  sulphide  as  hydrogen  sulphide  by  means  of  hydro- 
chloric acid  and  the  hydrogen  sulphide  titrated  with  a  standard 
solution  of  iodine. 


Fig.  3. 


50  METALLURGICAL  ANALYSIS 

Apparatus  required — A  flask,  A,  of  about  300  c.c.  capacity, 
provided  with  a  doubly  perforated  rubber  stopper.  See  Fig.  3. 
Through  one  of  the  holes  is  passed  a  separating  funnel,  B,  and 
through  the  other  hole  is  passed  a  bent  tube,  D,  extending  to 
within  two  or  three  inches  of  the  bottom,  of  an  eight  inch  test 
tube,  C. 

Solutions  Required — I.  Ammoniacal  Solution  of  Cadmium 
Chloride ;  prepared  as  follows :  Dissolve  13  grams  of  cadmium 
chloride  in  water,  add  65  c.c.  of  strong  ammonia  and  dilute  to 
a  volume  of  one  liter. 

II.  Standard  Iodine  Solution,  of  such  strength  that  one  c.c. 
is  equivalent  to  .0005  gram  of  sulphur.  The  reaction  between  the 
hydrogen  sulphide  and  the  iodine  is: 

H0S+2l=2HI+S. 

Then 

At.  wt.  of  S   :  2  (at.  wt.  of  I)  =.0005   :  x. 
32   :  253.7   : :  .0005    :  x. 

X  r=  .003965  gram  of  iodine,  the  amount  required  to  be  present 
in  each  cubic  centimeter  of  the  iodine  solution,  or  3.965  grams 
per  liter.  The  solution  may  be  prepared  from  decinormal  solution 
of  iodine  by  taking  313.3  c.c.  and  diluting  with  water  to  one 
liter. 

The  solution  may  be  prepared  from  iodine  as  follows :  Weigh 
four  grams  of  iodine  and  place  it  in  a  mortar  with  about  six 
grams  of  potassium  iodide  and  triturate  with  small  portions  of 
water  until  all  is  dissolved.  Dilute  the  solution  to  one  liter  vol- 
ume and  mix  thoroughly.  Standardize  the  solution  by  means 
of  a  standard  solution  of  sodium  thiosulphate,  containing  about 
eight  grams  of  the  salt  per  liter ;  the  exact  strength  of  which  may 
be  determined  by  means  of  a  standard  potassium  bichromate  or 
permanganate  solution  as  follows:  Take  10  c.c.  of  the  potassium 
bichromate  solution  in  a  number  4  beaker,  add  a  little  water  and 
about  one  gram  of  potassium  iodide.  Add  a  little  hydrochloric 
acid  and  stir  a  few  moments.  The  reaction  is : 

K2Cr2O7+6KI+i4HCl  =  8KCl+2CrCl3+6I+7H2O. 

Dilute  with  water  and  titrate  the  liberated  iodine  with 
the  thiosulphate  solution  using  starch  indicator,  toward  the  end 
of  the  reaction.  The  reaction  is : 

2l+2Na2S208=2NaI+Na2S400. 


METALLURGICAL  ANALYSIS  51 

.  Calculate  the  strength  of  the  thiosulphate  solution.  Now 
fix  the  strength  of  the  iodine  solution  from  the  standard  thiosul- 
phate solution  by  titration,  using  the  starch  indicator.  Dilute 
the  iodine  solution  with  water  to  the  strength  i  c.c.  =  .0005  gram 
sulphur. 

Process — Weigh  into  flask  A  5  grams  of  the  drillings.  Place 
in  the  test  tube  C,  about  10  c.c.  of  the  cadmium  chloride  solu- 
tion and  add  water  until  the  test  tube  is  about  two-thirds  full. 
Connect  the  test  tube  with  the  generating  flask  A.  Slowly  add 
by  means  of  the  separating  funnel,  75  to  100  c.c.  of  dilute  hydro- 
chloric acid  (sp.  gr.  i.i)  to  the  drillings.  When  about  all  of 
the  drillings  are  dissolved  heat  to  boiling  a  few  minutes,  and 
before  removing  the  heat  disconnect  the  test  tube. 

Pour  the  contents  of  the  test  tube  into  a  large  beaker,  dilute 
to  about  400  c.c.  Acidify  the  solution  with  hydrochloric  acid 
and  titrate  with  the  standard  iodine  solution,  using  the  starch 
indicator.  Do  not  wait  for  the  precipitate  of  cadmium  sulphide  to 
dissolve  before  commencing  the  titration. 

Each  cubic  centimeter  of  the  iodine  solution  required  equals 
.01  per  cent,  of  sulphur.  Results  on  the  same  sample,  obtained  by 
different  analysts,  should  agree  within  .005  per  cent. 

References  : 

Am.  Chem.  Jour.,  Vol.  XXVII,  page  500. 

G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.   XVIII,  page  406. 

G.  Auchy,  Jour.  Am.  Chem.  Soc.,  Vol.  XXIII,  ^ 


F.   C.   Phillips,  Jour.  Am.   Chem.   Soc..  Vol.    XVIII,  page   1079. 
F.  C.  Phillips,  Jour.  Am.  Chem.  Soc.,  Vol.  XVII,  page  891. 
A.  A.  Blair,  Jour.  Am.  Chem.  Soc.,  Vol.  XIX,  page  114. 
T.  M.  Drown,  Trans.  Am.  Inst.  Min,  Engrs.,  Vol.  X,  page  187. 
T.  M.  Drown,  Trans.  Am.  Inst.  Min.  Engrs.,  Vol.  II,   page  224. 
T.  M.  Drown,  Trans.  Am.  Inst.tMin.  Engrs.,  Vol.  XII.  page  507. 
C.  B.  Dudley,  Jour.  Am.  Chem.  Soc.  Vol.  XV.,  page  514. 


B AMBERS    METHOD    FOR    SULPHUR   IN    PIG    IRON. 

Dissolve  5  grams  in  strong  nitric  acid,  add  two  to  five  grams 
of  potassium  nitrate,  evaporate  to  dryness  in  a  platinum  or  por- 
celain dish,  and  ignite.  Treat  with  water,  with  the  addition  of  a 
little  sodium  carbonate,  filter,  and  wash  with  water  containing  a 
little  sodium  carbonate.  Acidulate  with  a  little  hydrochloric  acid, 
evaporate  to  dryness,  redissolve  in  water  with  a  few  drops  of 
hydrochloric  acid,  and  precipitate,  boiling  with  barium  chloride. 


52  METALLURGICAL  ANALYSIS 

Method  suitable  for  pig  iron  containing  sulphur  in  such  a  form 
that  it  is  not  acted  upon  by  HNO3,  HC1  or  aqua  regia. 

WIBORGH'S  COLOR  METHOD  FOR  SULPHUR  IN  IRON  AND  STEEL. 

Weigh  .8  to  I  gram  of  the  drillings  into  the  generating  flask 
A,  (See  Fig.  4)  and  fill  the  flask  about  one-third  full  of  water. 
The  cylinder  B,  is  then  adjusted,  and  the  water  in  the  flask 
heated  to  boiling.  A  rubber  washer,  C,  is  then  placed  on  top  of 
the  cylinder,  followed  by  the  prepared  cloth,  D,  (saturated  with  a 
solution  of  cadmium  chloride),  the  second  rubber  washer,  E,  and 
the  wooden  ring,  F,  the  whole  being  firmly  clamped  together  by 
two  steel  clamps,  G. 


Fig.  4. 

Be  sure  that  the  top  of  the  cylinder  is  in  a  horizontal  position. 
Heat  the  flask,  and  as  soon  as  the  cloth  is  moistened  and  the  air 
driven  out  of  the  apparatus,  admit  about  12  c.c.  of  dilute  sulphur- 
ic acid  (i  to  4)  through  the  side  tube  H,  and  apply  gentle  heat, 
till  the  sample  is  in  solution.  The  cloth  is  then  removed,  dried  on 
a  blotting  or  filter  paper  and  compared  with  the  standard  colors. 

References : 

Jour.  Am.  Chem.  Soc.,  Vol.  VI,  page  301. 

F.  P.  Treadwell,  Analyttechen  Chemic.,  Vol.,  II,  page  227. 


METALLURGICAL  ANALYSIS  53 

DETERMINATION  OF  SILICON  IN  PIG  IRON,  CAST 
IRON  AND  STEEL. 

BROWN'S  METHOD — Treat  one  gram  of  the  pig  or  cast  iron  drill- 
ings in  a  four  inch  casserole  with  30  c.c.  of  silicon  mixture  (i  part 
concentrated  H2SO4  and  2  parts  HNO^  sp.  gr.  1.2).  For  steel 
treat  about  5  grams  of  the  drillings  with  100  c.c.  of  silicon  mix- 
ture. Cover  the  dish  with  a  glass  cover.  At  first  keep  the  dish  well 
covered,  but  after  the  violent  action  ceases,  pull  the  cover  a  little 
to  one  side  and  evaporate  until  fumes  of  sulphur  tri-oxide  appear. 
Cool,  add  from  150  to  200  c.c.  of  water  and  a  little  hydrochloric 
acid.  Heat  to  dissolve  the  ferric  sulphate,  filter  hot,  wash  with  di- 
lute hydrochloric  acid,  and  then  with  hot  water,  ignite,  cool  and 
weigh  SiO.,.  Calculate  the  per  cent,  of  silicon. 

The  silica  should  be  perfectly  white.  If  it  is  colored  with 
oxide  of  iron,  after  weighing  it,  add  two  or  three  drops  of  con- 
centrated sulphuric  acid  and  four  or  five  c.c.  of  hydrofluoric  acid. 
Eavporate  to  dryness,  ignite,  cool  and  weigh  again.  The  loss  of 
weight  gives  the  amount  of  silica. 

Calculate  the  per  cent,  of  silicon. 

Chemical  analyses  of  the  same  sample  made  by  different  chem- 
ists should  agree  within  .01  per  cent. 

Chromic  Acid  Modification  of  Drown' s  Method  for  Silicon  in 
Pig  Iron — Treat  one  gram  of  the  pig  iron  in  a  4  inch  casserole 
with  10  to  20  c.c.  of  water  and  25  c.c.  of  silicon  mixture  (i  part 
H0SO4,  sp.  gr.  1.84  and  2  parts  HNO3,  sp.  gr.  1.2).  Heat  gently 
until  the  violent  action  ceases.  When  dissolved,  evaporate  rapidly 
until  the  iron  sulphate  becomes  insoluble,  and  commences  to  sput- 
ter against  the  cover  glass.  Remove  from  the  lamp  and  while  hot 
add  15  c.c.  of  a  water  solution  of  chromic  acid  (120  gr.  per  liter). 
Boil  again  as  before  until  the  chromic  acid  crystallizes  out.  Re- 
move from  the  lamp  and  add  hot  water,  slowly  at  first,  boil  for  a 
few  minutes  or  until  dissolved  and  clear.  Filter,  wash  the  chromic 
acid  out  of  the  filter  with  hot  water,  wash  once  with  hydrochloric 
acid  (sp.  gr.  1.06)  and  then  wash  three  or  four  times  with  hot 
water.  Ignite,  cool,  and  weight  SiO.,.  Calculate  the  per  cent,  of  Si. 

Precautions — The  evaporation  with  the  chromic  acid  must  not 
be  carried  too  far,  otherwise  insoluble  salts  are  formed.  On  the 
other  hand  if  the  heat  is  not  continued  long  enough,  the  graphite 


54  METALLURGICAL  ANALYSIS 

will  not  all  be  oxidized.  The  small  amount  of  graphite  occasion- 
ally remaining  is  very  rapidly  burned  off  in  the  ignition.  A  slight 
green  tint  in  the  ash  does  not  materially  affect  the  result.  This 
treatment  with  chromic  acid  not  only  removes  the  carbon,  but 
renders  the  filtration  much  more  rapid.  Time  required,  from  20 
to  30  minutes. 

References : 

T.   M.   Drown,  Trans.  Am.  Inst.  Min.  Engs.,  Vol.  VII,  page  346. 
D.   H.  Brown,  Jour.  Anal.  &  App.  Chem.,  Vol.  VI,  page  452. 


DETERMINATION  OF  ALUMINUM  IN  IRON 
AND  STEEL. 

Treat  i  gram  of  the  iron  or  steel  in  a  number  3  beaker,  with 
a  mixture  of  15  c.c.  of  nitric  acid  (sp.  gr.  1.2)  and  10  c.c.  of  hy- 
drochloric acid  (sp.  gr.  i.i).  Cover  the  beaker  with  a  glass 
cover  and  heat  until  sample  is  dissolved.  Remove  the  cover  and 
evaporate  to  dryness.  Take  up  in  15  c.c.  of  concentrated  hydro- 
chloric acid,  dilute,  filter  on  ashless  filter  paper,  and  wash  with 
water.  Add  20  c.c.  of  a  10%  solution  of  hydrogen  sodium  phos- 
phate and  continue  as  in  the  determination  of  alumina  in  iron 
ores.  See  page  33. 

Calculate  per  cent,   aluminum. 


INTERNATIONAL  ATOMIC  WEIGHTS 


0=16           H=l 

Aluminium.  .  . 

.Al 

27.1 

26.9 

Molybdenum 

.Mo 

96.0 

95-3 

Antimony.  ... 

.Sb 

120.2 

II9-3 

Neodymium. 

.Ne 

143-6 

142.5 

Argon  . 

.A 

•jq  Q 

39-6 

Neon 

20. 

IQ  Q 

Arsenic 

As 

OV*  7 

75.0 

74.4 

Nickel  

.Ni 

58.7 

iy.y 

58.3 

Barium  

.Ba 

137.4 

136.4 

Nitrogen  

.N 

14.04 

13.93 

Bismuth  

.Bi 

208.5 

206.9 

Osmium  

.Os 

191 

189.6 

Boron  

.B 

ii 

10.9 

Oxygen  

..0 

16.00 

15.88 

Bromine  

.Br 

79.96 

79-36 

Palladium... 

.Pd 

106.5 

105.7 

Cadmium  

.Cd 

112.4 

in.  6 

Phosphorus  . 

.P 

31-0 

30.77 

Caesium  

Cs 

133 

132 

Platinum  .... 

..Pt 

194-8 

193.3 

Calcium 

Ca 

40.1 

39-8 

Potassium  .  .  . 

..K 

39.15 

38.86 

Carbon  

c 

12.00 

11.91 

PraseodymiumPr 

140.5 

IV)  4. 

Cerium  

.Ce 

I40 

139 

Radium  

..Ra 

225 

Aoy.<+ 
223.3 

Chlorine 

Cl 

35-45 

35.i8 

Rhodium  

..Rh 

103.0 

102.2 

Chromium  

.Cr 

52.1 

51-7 

Rubidium  .  .  . 

..Rb 

85-4 

84.8 

Cobalt 

.Co 

59.0 

58.56 

Ruthenium.. 

..Ru 

101.7 

100.9 

Columbium 

Samarium  .  .  . 

..Sm 

150 

148.9 

(Niobium). 

.Cb 

94 

93-3 

Scandium  .  .  . 

..Sc 

44-1 

43-8 

Copper  

.Cu 

63.6 

63.1 

Selenium  

..Se 

79-2 

78.6 

Erbium 

.E 

1  66 

164.8 

Silicon  

..Si 

28.4 

28.2 

Fluorine  

.F 

19 

18.9 

Silver  

..Ag 

107-93 

107.12 

Gadolinium.. 

.Gd 

156 

155 

Sodium 

.Na 

23-05 

22.88 

Gallium 

Ga 

70 

69.5 

Strontium  .  . 

..Sr 

87.6 

86.94 

Germanium.. 

.Ge 

72.5 

71.9 

Sulphur  

..S 

32.06 

31-83 

Glucinum  

Tantalum  .  .  . 

..Ta 

183 

181.6 

(Beryllium) 

.Gl 

9-1 

9-03 

Tellurium  .  .  . 

..Te 

127.6 

126.6 

Gold  

.Au 

197.2 

195.7 

Terbium  

..Tb 

160 

158.8 

Helium  

.He 

4 

4 

Thallium  

..Tl 

204.1 

202.6 

Hydrogen.  .. 

.H 

1.008 

1.  000 

Thorium  

..Th 

232.5 

230.8 

Indium  

.In 

114. 

113.1 

Thulium  

..Tm 

171 

169.7 

Iodine  

.1 

126.85 

125.90 

Tin  

..Sn 

119.0 

llS.l" 

Iridium  

.lr 

193.0 

191.5 

Titanium  

..Ti 

48.1 

47-7 

Iron  

.Fe 

55-9 

55.5 

Tungsten  .  .  . 

..W 

184.0 

182.6 

Krypton 

.K 

81.8 

81.2 

Uranium  

..U 

238.5 

236.7 

Lanthanum. 

.La 

138.9 

137.9 

Vanadium.  . 

..V 

51.2 

50.8 

Lead  

.Pb 

206.9 

205.35 

Xenon  

..X 

128 

127 

Lithium  

.Li 

7.03 

6.98 

Ytterbium  .  . 

..Yb 

173-0 

171.7 

Magnesium.. 

-Mg 

24.36 

24.18 

Yttrium  

..Yt 

89.0 

88.3 

Manganese.  . 

.Mn 

55.0 

54.6 

Zinc 

Zn 

6;   , 

, 

Mercury  

•Hg 

20C.O 

198.5 

Zirconium  .  . 

..Zr 

uj*4 
90.6 

04.9 
89.9 

INDEX 

Alumina,  in  iron  ores,  determination  of 34 

Alumina,  in  slags,  determination  of 14,  18 

Aluminum,  in  iron  and  steel,  determination  of       .       .       .  54 

Ammonium  molybdate,  reagent 24 

Ammonium  molybdate  solution,  method  of  standardizing     .  8 

Arsenic,   in   arsenic   ores,   determination  of        ....  9 

Barium,  in  slags,  determination  of 12 

Calcium,   in  iron  ores,  determination  of 40 

Calcium,  in  slags,  determination  of 

by    Gravimetric    method 16 

by  Volumetric  method 13 

Carbonic  acid  gas,  in  iron  ores,  determination  of  ...  38 
Carbon,  total,  in  iron  and  steel,  determination  of 

by  Chromic  acid  method 40 

by  combustion  in  the  Shimer  crucible       ....  43 
Carbon,  combined,  in  iron  and  steel,  determination  of 

by  the  Color  method 45 

Carbon,  graphitic,  in  iron  and  steel,  determination  of  -44 

Coal  and  coke,  methods  for  the  analysis  of  ....  19 
Chromium,  in  chrome  ore,  determination  of  .  .  .11 
Copper,  in  copper  ores,  determination  of 

by  the  Iodide  method I 

by  the   Cyanide   method 3 

by  the  Electrolytic  method       .        .        .        .        .        .        .5 

by  the  Color  method 5 

Copper,  in  slags,  mattes,  etc.,  determination  of       .        .       .  18 

Ferrous  oxide,  in  iron  ores,  determination  of      ....  38 

Ferrous  sulphate  solution,  method  of  standardizing       .       12,  30 

Iodine  solution,  method  of  standardizing 50 

Iron,  in  iron  ores,  determination  of 

by  Standard  solution  of  KMnO* 21 

by  Standard  solution  of  K-..Cr2O7 22 

Iron  ores,  method  for  complete  analysis  of       .       .        .  38 

Jones's  reductor,  use  of,  in  determining  phosphorus       .        .  26 

Lead,  in  lead  ores,  determination  of,  by  Alexander's  method  8 

Lead,  in  slags,  mattes,  etc.,  determination  of  ....  17 
Manganese,  in  iron  ores,  determination  of 

by  Volhard's  method 28 

by  Ford- Williams'   method 29 

by    Julian's    method 31 


58  INDEX 

Manganese,  in  iron  and  steel,  determination  of 

by  Volhard's  method 47 

by  Ford- Williams'  method 48 

by    Julian's    method 48 

by  Color  method 48 

Manganese,   in   slags,   determination   of       .        .       .        .       15,    17 

Moisture,  in  iron  ores,  determination  of 37 

Nitric  acid,  method  of  preparing  a  standard  solution  .  .  27 
Phosphorus,  in  iron  ores,  determination  of 

by    Emmerton's    method 23 

by   the    Acidimetric    method 26 

by    Wood's    method        ....  27 

Phosphorus,  in  iron  and  steel,  determination  of       ...       47 

Phosphorus,  in  slags,  determination  of 14 

Potassium  permanganate  solution,  method  of  standardizing  .  21 
Potassium  bichromate  solution,  method  of  standardizing  .  22 
Potassium  ferrocyanide  solution,  method  of  standardizing  .  6 
Potassium  cyanide  solution,  method  of  standardizing  .  .  3 
Potassium  sulphocyanate  solution,  method  of  standardizing  IO 
Potassium  hydroxide,  method  of  preparing  standard  solution  26 

Silica,  in  iron  ores,  determination  of 32 

Silica,  in  slags,  determination  of 12,  14,  16 

Silicon,  in  iron  and  steel,  determination  of  .  .  .  -53 
Slags,  methods  for  the  analysis  of  .  .  .  .12,  14,  16 

Sodium  hydroxide,  method  of  preparing  a  standard  solution  .  26 
Sodium  thiosulphate,  method  of  preparing  and  standardizing  i,  50 

Sulphur,  in  iron  ores,  determination  of 31 

Sulphur,  in  slags,  determination  of 16,    19 

Sulphur,  in  coal  and  coke,  determination  of  ....  20 
Sulphur,  in  iron  and  steel,  determination  of 

by  Oxidation  and  Solution 48  51 

by  Evolution  method 49 

by  Wiborgh's  color  method 52 

Titanium,  in  iron  ores,  determination  of        .        .       .        .        .34 

by  Gooch's  method          . 35 

by  Betters  method 36 

by  Willer's  color  method 37 

Zinc,  in  zinc  ores,  determination  of,  by  Low's  method  .  .  6 
Zinc,  in  slags,  determination  of 18 


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